Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Three identical horizontal rods AB, CD and EF each of length 2m are on a smooth horizontal surface. Rod CD is at rest while the rods AB and EF are purely translating with equal and opposite velocities of magnitude 5 m/s.The ends B and E collide simultaneously with the ends C and D respectively, and the rods rigidly join just after the collisions.Find the angular speed of the system in rad/s just after the collision.

Answer» Applying conservation of the angular momentum of the system of three rods about midpoint of the rod CD
`=mxx5xx1+mxx5xx1=[2((m2^(2))/12+m(sqrt(2))^(2))+(m2^(2))/12]rArr omega=30/15=2 rad//sec`
2.

At what point does the line (x - 1)/1 = (y - 2)/2 = z/0 cut the plane 3x – y + z = 0(A) (0,0,0) (B) (1,2,0) (C) (0,1,1) (D) None of these

Answer»

Correct option:

(A) (0,0,0)

3.

How many tangents can have a circle?(a) 1(b) 2(c) infinity(d) 3

Answer»

How many tangents can have a circle  infinity

4.

The Ratio between side and diagonal of a sauare is(a) √2:1(b) 1:√2(c) 1:2(d) 2:1

Answer»

The Ratio between side and diagonal of a sauare is 1:2

5.

A point P moves on the parabola x2 – 2x + 4y – 11 = 0. The equation of the locus of mid-point of line segment PS is (where S is the focus of the parabola)

Answer»

x2 – 2x + 4y – 11 = 0
⇒ x2 – 2x – 11 = -4y 
⇒ x2 – 2x + 1 - 12 = -4y 
⇒ (x - 1)2 = 4(-1)(y - 3) 
From here we can identify the focus.
As in (x - h)2 = 4p (y - k) the focus is given by (h, k + p)
The directrix is y = k - p
Here focus is (1, 4) and directrix is y = 4

Now it's easy to solve as the locus formed by that point will also be a parabola with same focus and distance will be half. 

6.

Find the locus of the point which is equidistant from the points ( -3, 1) and (7, 5).

Answer»

Let A = (-3, 1) and B = (7, 5). Let P = (x, y).

Then AP = PB ⇔ (AP)2 = (PB)2

⇔ (x + 3)2 + (y -1)2 = (x -  7)2 + (y - 5)2

⇔  6x - 2y + 10 = 14x -  10y + 74

⇔ 20 x + 8y - 64 = 0

⇔ 5x + 2y - 16 = 0 

Hence, the equation of  5x + 2y - 16 = 0

7.

If the sum of the distances of a point from two perpendicular lines in a plane is 1, then prove that its locus is a square. 

Answer»

Take the two perpendicular lines as coordinate axes. P(x, y) is a point on the locus ⇔|x| + |y| = 1. This implies that

x + y = 1

x - y = 1

-x + y = 1

 -x - y = 1

 These lines form a square.

8.

Match the items of Column I with those of Column II.Column IColumn II(A) Equation of the line with x-intercept 4 and passing through the point (2, 3) is(p) x + 4y - 8 = 0(B) Equation of the line passing through (4, 1) and forming a triangle with positive coordinate axes whose area is 8 sq. unit is(q) 3x - 2y = 12C) Equation of the line with equal intercepts on the axes and is passing through the point (2, 5) is(r) x + y = 7 = 0(D) Equation of the line which makes an angle of 135° with the positive direction of the axis and makes an intercept of 8 on y-axis is(s) 2x + y + 1= 0(t) x + y - 8 = 0

Answer»

Equation of the line is

x/4 + y/b = 1

It passes through (2, 3). This implies that

2/4  + -3/b = 1 ⇒ -3/b = 1/2 ⇒ b = -6

Hence, the equation of the line is

x/4 - y/6 = 1

3x - 2y = 12= 0

Answer: (A)  (q)

(B) Let  x/a + y/b = 1

It passes through (4, 1) and forms a triangle with positive axes having area 8. Therefore

4/a + 1/b = 1  ...(1)

and 1/2(ab) = 8

From Eqs. (1) and (2), a = 8 and b = 2. Hence, the equation of the line is

x/8 + y/2 = 1  or x + 4y - 8 = 0

Answer: (B)  (p)

(C) Equation of the line with equal intercepts on the axes is

x/a + y/a = 1 or  x + y = a

This passes through the point (2, 5) implies that a = 7. Hence, the line is

x + y - 7 = 0

Answer: (C)  (r)

(D) Let the line be y =  (tan 135°)x + c where c = 8. That is, y = -x + 8 or x + y = 0. 

Answer: (D)  (t)

9.

Passage: Consider the straight line 3x + y + 4 = 0. Answer the following questions. (i) The point on the line 3x + y + 4 = 0 which is equidistant from the points ( 5, 6) and (3, 2) is (A)  ( 1, 1)(B)  ( 2, 2) (C)  ( 3, 5)(D)  ( 1 3 , 3)(ii)  Equation of the line passing through the point (1, 1) and perpendicular to the given line is(A)  x - 3y + 4 = 0 (B)  x - 3y + 5 = 0(C)  x -  3y - 4 = 0(D)  x -  3y + 2 = 0(iii) If the line y + 5 = k(x - 3) is parallel to the given line then the area of the triangle formed by this line and the coordinate axes (in sq. units) is(A)  8/3(B)  16/3(C)   4(D)   5

Answer»

Correct option  (i) (B),(ii) (D),(iii) (A)

Explanation :

 (i)  Let A = (5 ,6) and B = (3, 2). The slope of AB is

and the midpoint of AB = (-1, 4). Hence, the perpendicular bisector of the segment (bar)AB is y - 4 = 2(x + 1) or 2x - y + 6 = 0 . Solving this equation and the given line equations, we have x = -2 and y = 2. Thus, (-2, 2) is the point on the given line which is equidistant from both A(-5 6) and B(3, 2).

 (ii) Line perpendicular to the given line is of the form

y = 1/3x + c

This line passes through (1, 1). It implies that

1 = 1/3 + c ⇒ c = 2/3

Thus, the required line is

y = x/3 + 2/3 or x - 3y + 2 = 0

(iii) The line y + 5 = k(n - 3) is parallel to the given line ⇒ k = -3. That is, 

3x + y = 4

or  x/(4/3) + y/4 = 1

Hence, the area of the triangle is

1/2(4/3)(4) = 8/3

10.

The ratio in which the line 3x - y + 6 = 0 divides the line joining the points A(3, 4) and B( 2, 1) is (A)  2:11(B)  9:2(C)  11:1(D)  1 : 12

Answer»

Correct option  (C)  11 : 1

Explanation :

L ≡ 3x - y + 6 = 0, A = (3,4),B = (-2,1)

L11 = 3(3) - 4 + 6 = 11, L22 = 3(-2) -1 + 6 = -1

 Hence, the ratio AP : PB is

-L11: L22 = (-11) : (-1) = 11 : 1

11.

What is the time duration of the game of Kabaddi?

Answer»

The duration of Kabaddi game is 20-5-20 and for junior boys and girls is 15-5-15.

12.

Mention the number of officials conducting the game of Kabaddi?

Answer»

Officials in Kabaddi are:

  1. One referee
  2. Two umpires
  3. Two lines-men
  4. One scorer.
13.

How is the game of Kabaddi Match decided?

Answer»

Any team which gets more points shall be winner. In case of draw 5 extra minutes will be given until the match is decided.

14.

The number of 3 x 3 non-singular matrices, with four entries as 1 and all other entries as 0, is(1) 5(2) 6(3) at least 7(4) less than 4

Answer»

(3) at least 7

First row with exactly one zero; total number of cases = 6

First row 2 zeros we get more cases

Total we get more than 7.

Directions: Questions Number 72 to 76 are Assertion – Reason type questions. Each of these questions contains two statements.

Statement-1: (Assertion) and Statement-2: (Reason)

Each of these questions also has four alternative choices, only one of which is the correct answer.

You have to select the correct choice.

15.

If two tangents drawn from a point P to the parabola y2 = 4x are at right angles, then the locus of P is(1) 2x + 1 = 0(2) x = -1(3) 2x - 1 = 0(4) x = 1

Answer»

(2) x = –1 

The locus of perpendicular tangents is directrix. i.e, x = –a; x = –1

16.

An electric oven of 2kW power rating is operated in a domestic electric circuit (220V) that has a current rating of 5A. What result do you expect? Explain.

Answer»

Given: Power = 2kW = 2000W 

Current = 5A 

Voltage = 220V 

∴ Power = Current x Voltage

⇒ Current = \(\frac{Power}{Voltage}\) = \(\frac{2000}{220}\) = 9 A

Thus, the current exceeds the current rating of 5A. Therefore, either the fuse will burn out and if there is no fuse, then overloading will cause melting of wires which may result in short-circuiting or a fire.

17.

The acceleration versus time graph for a particle moving along a straight line is shown in the figure. If the particle starts from rest at t = 0, then its speed at t = 30 sec will be : A. `20m//sec`B. `40m//sec`C. `0m//sec`D. `-40m//sec`

Answer» Correct Answer - B
The acceleration ……..
For a - t curve
speed = |velocity|
speed (at t = 30 sec) `= |10xx4-4xx20|`
`= |40-80| = |-40| = 40m//sec`.
18.

The acceleration versus time graph for a particle moving along a straight line is shown in the figure. If the particle starts from rest at t = 0, then its speed at t = 30 sec will be :

Answer» Correct Answer - 4
Total area under curve `Deltavimpliesintadtimplies+10xx4-20xx4implies-40`
19.

Your classmate has written a book of short stories which has won an award for being the best book by a new author. Write a review of the book for your school magazine.

Answer»

It is the book review for the famous book, THE INVISIBLE MAN

Ralph Ellison’s The Invisible Man:

An extremely powerful story of a young Southern Negro, from his late high school days through three years of college to his life in Harlem.

His early training prepared him for a life of humility before white men, but through injustices- large and small, he came to realize that he was an "invisible man". People saw in him only a reflection of their preconceived ideas of what he was, denied his individuality, and ultimately did not see him at all. This theme, which has implications far beyond the obvious racial parallel, is skillfully handled. The incidents of the story are wholly absorbing. The boy's dismissal from college because of an innocent mistake, his shocked reaction to the anonymity of the North and to Harlem, his nightmare experiences on a one-day job in a paint factory and in the hospital, his lightning success as the Harlem leader of a communistic organization known as the Brotherhood, his involvement in black versus white and black versus black clashes and his disillusion and understanding of his invisibility- all climax naturally in scenes of violence and riot, followed by a retreat which is both literal and figurative. Parts of this experience may have been told before, but never with such freshness, intensity and power.

20.

write an article to be published in a local newspaper expressing your concern for the rising number of unemployed youth in our country

Answer»

Youth unemployment is the situation of young people who are looking for a job, but cannot find a job, with the age range being that defined by the United Nations as 15–24 years old. An unemployed person is defined as someone who does not have a job but is actively seeking work. In order to qualify as unemployed for official and statistical measurement, the individual must be without employment, willing and able to work, of the officially designated "working age" (often from the teens to the mid-60s) and actively searching for a position. Youth unemployment rates tend to be higher than the adult rates in every country in the world.

Causes -There are multiple and complex causes behind youth unemployment. Among them, the quality and relevance of education, inflexible labour market and regulations, which in turn create a situation of assistance and dependency, are the main causes discussed today.

Effect - Unemployed youth has been called "a lost generation": not only because of productivity lost but also because of the long-term direct and indirect impact unemployment has on young people and their families. Unemployment has been said to affect earnings for about 20 years. Because they aren't able to build up skills or experience during their first years in the workforce, unemployed youth see a decrease in lifetime earnings when compared to those who had steady work or those who were unemployed as an adult. A lower salary can persist for 20 years following the unemployed period before the individual begins earning competitively to their peers.[10] Widespread youth unemployment also leads to a socially excluded generation at great risk for poverty.

21.

Use for dramatic works involving the downfall or destruction of the protagonist due to character flaws, catastrophe, or reversal of fortune. (a) Comedy (b) Monologue(c) Tragedy (d) Historical Plays

Answer»

Correct Answer is : (c) Tragedy

22.

write an article for your school magazine entitled Global Warming : Are we heading Towards a major Catastrophe?

Answer»

One of the most dangerous threats to life on earth is the increase in pollution which is caused because of the increase in the concentration of carbon dioxide and carbon monoxide in the environment. Since the last century, the immense increase in pollution in nature has been the cause of many harmful effects. Increase in Global warming, reduction in the quality of air and water and an increase in life-threatening diseases are some of the main effects of pollution. Hence, it is the need of the hour to look into the issue and find alternatives to them.  

One of the important element which keeps the life going on this earth is oxygen. The life-supporting oxygen is the product which we receive from the trees. Hence, trees are the basic manufacturer of oxygen which helps to grow life on Earth. Since last century there has been immense cutting down of the trees for different uses. The man has been cutting trees so as to make the life easy. In this run, the man himself has become the cause of his downfall. Trees purify the air and help in keeping the atmosphere cool. Cutting down of the trees has encouraged global warming which is a global concern. A rise in temperature has been noticed which is not a good symbol for life on Earth. Hence, tree plantation should be encouraged and the cutting of the trees should be minimized.  

23.

How many terms are there in the AP 7, 11, 15, …, 139 ?

Answer»

Given AP is 7, 11, 15, …., 139. 

First term of AP is a = 7. 

And common difference of AP is d = a2 – a1 = 11 – 7 = 4. 

Let nth term of AP is 139. 

∴ a + (n – 1) d = 139. (∵ nth term of AP is given by an = a + (n – 1) d) 

⇒ 7 + (n – 1)4 = 139 (∵ a = 7 & d = 4) 

⇒ 4(n – 1) = 139 – 7 = 132 

⇒ n – 1 = 132 4 = 33 

⇒ n = 33 + 1 = 34. 

Hence, total term in given AP is 34.

24.

Find the sum of all odd integers between 2 and 100 which are divisible by 3.

Answer»

The odd integers between 2 and 100 which is divisible by 3 are 3, 9, 15, ..., 99. 

First and last odd integer between 2 and 100 which is divisible by 3 are 3 and 99 respectively. 

First term of given sequence is a = 3. 

And common difference of AP is d = a2 – a1 = 9 –3 = 6. 

Let 99 is nth term of sequence 3, 9, 15, .………., 99. 

∴ a + (n – 1) d = 99. (∵ an = a + (n – 1) d) 

⇒ 3 + (n – 1)6 = 99 (∵ a = 3 & d = 6) 

⇒ 6(n – 1) = 99 – 3 = 96 

⇒ n – 1 = \(\frac{96}{6}\) = 16 

⇒ n = 16 + 1 = 17. 

Now, sum of sequence 3, 9, 15, ………, 99 = \(\frac{n}{2}\)[a + an]

= \(\frac{17}{2}\) [3 + 99] (∵ n = 17, a = 3 & an = 99) 

= \(\frac{17}{2}\) × 102 = 17 × 51 = 867. 

Hence, the sum of all odd integers between 2 and 100 which are divisible by 3 is 867.

25.

B If \( S \) and \( T: R^{2} \rightarrow R^{2} \) are a linear transformation defined as \( S(x, y)= \) \( (0, x+y) \) and \( T(x, y)=(2 x, 3 y) \). Find \( S+T(x, y) \) and \( T(u-2 v) \) if \( u=(-1,5) \& v=(6,-3) \).

Answer»

S(x, y) = (0, x + y)

T(x, y) = (2x , 3y)

(S + T) (x, y) = S(x, y) + T(x, y)

\(\)= (0, x + y) + (2x, 3y)

= (2x, x + 4y)

U = (-1 , 5)

V = (6, -3)

U - 2V = (-1, 5) - 2(6, -3)

= (-1 -12, 5 + 6)

= (-13, 11)

T(U - 2V) = T(-13, 11) = (-26, 33).

26.

The distance (in km) of 40 engineers from their residence to their place of work were found as follows.5 3 10 20 25 11 13 7 12 3119 10 12 17 18 11 32 17 16 27 9 7 8 3 5 12 15 18 312 14 2 9 6 15 15 7 6 12What is the empirical probability that an engineer lives:(i) less than 7 km from her place of work?(ii) more than or equal to 7 km from her place of work?(iii) within 1/2 km from her place of work?

Answer»

(i) Total number of engineers = 40

Number of engineers living less than 7 km from their place of work = 9

Hence, required probability that an engineer lives less than 7 km from her place of work, P = 9/40

(ii) Number of engineers living more than or equal to 7 km from their place of work = 40 − 9 = 31

Hence, required probability that an engineer lives more than or equal to 7 km from her place of work, P = 31/40

(iii) Number of engineers living within 1/2 km from her place of work = 0

Hence, required probability that an engineer lives within 1/2 km from her place of work, P = 0

27.

In class 10A there are 30 boys and 20girls. In 10B there are 40 boys and 30girls. One student is to be selected from each class. In how many different ways we can select a pair of students. What is the probability of both being boys. What is the probability of getting one boy and one girl. What is the probability of getting at least one boy.

Answer»

 i. Total no. of possible pairs = 50 × 40 = 2000 

No. of pairs in which both are girls = 20 × 25 = 500

Probability of both being girls = \(\frac{500}{2000}=\frac{1}{4}\)

ii. No. of pairs in which both are boys = 30 × 15 = 450

Probability of both being boys = \(\frac{450}{2000}=\frac{9}{40}\)

iii. No. of pairs in which one is boy and one is girl = 2000 – (500 + 450) = 2000 – 950 = 1050

Probability of one being boy and one girl = \(\frac{1050}{2000}=\frac{21}{40}\)

iv. No. of pairs in which atleast one is boy = 1050 + 450 = 1500

Probability in which atleast one is boy = \(\frac{1050}{2000}=\frac{3}{4}\)

28.

In class 10A, there are 30 boys and 20 girls. In 10B, there are 15 boys and 25 girls. One student is to be selected from each class. i. What is the probability of both being girls? ii. What is the probability of both being boys? iii. What is the probability of one boy and one girl? iv. What is the probability of at least one boy?

Answer»

i. Total no. of possible pairs = 50 × 40 = 2000 

No. of pairs in which both are girls = 20 × 25 = 500

Probability of both being girls = \(\frac{500}{2000}=\frac{1}{4}\)

ii. No. of pairs in which both are boys = 30 × 15 = 450

Probability of both being boys = \(\frac{450}{2000}=\frac{9}{40}\)

iii. No. of pairs in which one is boy and one is girl = 2000 – (500 + 450) = 2000 – 950 = 1050

Probability of one being boy and one girl = \(\frac{1050}{2000}=\frac{21}{40}\)

iv. No. of pairs in which atleast one is boy = 1050 + 450 = 1500

Probability in which atleast one is boy = \(\frac{1050}{2000}=\frac{3}{4}\)

29.

There is one spot at one side of the cube, two on another side, three on the third side and so on. There are spots on all the six faces; in this order. Another cube which is marked in the same way is taken.a. If both the cubes are thrown, what is the probability that the total number of spots on the upper faces is 6?b. What is the probability that the sum of the spots on the upper faces is 9?c. What is the probability that the sum of the spots be one?d. What is the probability that the sum of the spots be a prime number?

Answer»

Total number of pairs 6 x 6 = 36

a. Pairs of spots with total number 6 are (1,5) (2,4) (3,3) (4,2) (5,1)

∴ Probability = \(\frac{5}{36}\)

b. Pairs with 9, (3,6) (4,5) (5,4) (6,3)

∴ Probability = \(\frac{4}{36}=\frac{1}{9}\)

c. Probability to be 1 = \(\frac{0}{36}=0\)

d. Pairs with total number of spots as prime number (1,1) (1,2) (1,4) (1,6) (2,1) (2,3) (2,5) (3,2) (3,4) (4,1) (4,3) (5,2) (5,6) (6,1) (6,5)

∴ Probability = \(\frac{15}{36}\)

30.

The ninth term of an AP is equal to 7 times the 2nd term and 12th term exceeds five times the third term by 2. Find the first term and common difference.

Answer»

We have, A9=7*a2 
a12=5a3+2 

So, 
a9=(a+d)7 
a12=5(a+2d)+2 

So, 
a+8d=7a+7d, 

d=6a 
a+11d=5a+10d+2, 
d=4a+2, 
2a=2, 
a=1 
d=6a=6 

So, first term is 1 & common difference is 6.

31.

In a pack of 52 cards, half are red and the rest are black. There are 4 Suits of 13 cards each and having the signs ‘hearts’, ‘spade’, ‘clubs’ and ‘diamond’. If a card is picked from this pack. a. What is the probability of it being black? b. What is the probability of it be in gaspade?c. What is the probability of it being a spade or a diamond?

Answer»

a. Total number of cards = 52

Number of black cards = 26

Probability of the picked card being black = \(\frac{26}{52}=\frac{1}{2}\)

b. No. of spade cards = 13

Probability of a picked card being spade = \(\frac{12}{52}=\frac{1}{4}\)

c. No. of cards spade or diamond =13 + 3 = 26

Probability of a picked card being spade or diamond = \(\frac{26}{52}=\frac{1}{2}\)

32.

There are 50 children in a class. Thirty of them are girls. There are 40 children in another class. 25 of them are boys. One student is taken from each class at random. What is the number of outcomes? How many outcomes contain both boys. How many outcomes contain both girls. How many outcomes have one boy and one girl?

Answer»

Total pairs = 50 × 40 = 2000

No. of pairs in which both are boys = 20 × 25 = 500

No. of pairs in which both are girls = 30 × 15 = 450

No. of pairs in which one is a boy and the other a girl = 30 × 25 + 20 × 15 = 750 + 300 = 1050

33.

Solve for 'x' : 1/(2a+b+2x) = 1/2a+1/b+1/2x, x≠0

Answer»

1/(2a+b+2x) - 1 / (2x) = 1 / 2a + 1 / b

(2x - 2a - b - 2x) / (2x)(2a+b+2x) = (2a + b) / 2ab

-(2a + b) / (2x)(2a+b+2x) = (2a + b) / 2ab

2a + b gets cancelled.

-2ab = (2x)(2a+b+2x)

-2ab = 4ax + 2bx + 4x2

4x2 + 2bx + 4ax + 2ab = 0

2x(2x + b) + 2a(2x + b) = 0

(2x +2a)(2x + b) = 0

2x + 2a = 0

x = - a

2x + b = 0

x = - b / 2

So, x = -a , -b/2

34.

Show that 28n cannot end with digit 0 for any natural number

Answer»

Solution:

If any number ends with the digit 0, it should be divisible by 10 or in other words, it will also be divisible by 2 and 5 as 10 = 2 × 5  
It can be observed that 5 is not in the prime factorisation of (22x7)or 28n 
Hence, for any value of n, 28n will not be divisible by 5.  
Therefore, 28n cannot end with the digit 0 for any natural number n.

35.

A box contains 400 electronic toy cars. Among them, 12 are defective. One toy is taken out at random. What is the probability thata. It is a defective toy. b. It is a non-defective toy.

Answer»

Total number of cars = 400

Number of defective toys = 12

Number of non-defective toys = 400 – 12 = 388

a. Probability of getting a defective toy = \(\frac{12}{400}=\frac{3}{100}\)

b. Probability of getting a non-defective toy = \(\frac{388}{400}=\frac{97}{100}\)

36.

A box contains 6 black and 4 white balls. If a ball is taken from it. What is the probability of it being black? And the probability of it being white?

Answer»

Total no. of balls = 10 

No. of black balls = 6 

No. of white balls = 4

Probability of it to be black = \(\frac{6}{10}=\frac{3}{5}\)

Probablitiy of to be white = \(\frac{4}{10}=\frac{2}{5}\)

37.

How many odd numbers are there below 25

Answer»

Answer is 12 odd numbers

38.

How many multiples of 7 are there in between 100 and 300?

Answer»

First multiple of 7 = 105 

Last multiple of 7 = 294 

Number of multiples = \(\frac{294-105}{7}+1=28\)

39.

What is the probability of occurring 53 Sundays in a leap year

Answer»

Leap year have 366 days. 

That is 52 weeks and 2 days. 

There two days are 

Sunday – Monday, Monday – Tuesday, Tuesday – Wednesday, Wednesday – Thursday, Thursday – Friday, Friday – Saturday, Saturday – Sunday. 

∴ Probability for to occur 53 Sunday is 2/7.

40.

Find the probability of getting  53 Sundays in a non-leap year?

Answer»

A non-leap year has 365 days

A year has 52 weeks. Hence there will be 52 Sundays.

52 weeks = 52 x 7 = 364 days .

365– 364 = 1day extra.

In a non-leap year there will be 52 Sundays and 1day will be left.

This 1 day can be Sunday, Monday, Tuesday, Wednesday, Thursday,friday,Saturday, Sunday.

Of these total 7 outcomes, the favourable outcomes are 1.

Hence the probability of getting 53 Sundays = 1 / 7.

41.

One box contains 8 black balls and 12 white balls. Another box contains 9 black and 6 white balls. One ball is taken from each box at random. What is probability of getting both black? What is the probability of getting both white? What is the probability of getting one black and one white?

Answer»

Total pairs = 20 x 15 = 300 

Number of pairs getting both black= 8 x 9 = 72

Probability of getting both black = \(\frac{72}{300}=\frac{6}{25}\)

Probability of getting one black and one white = \(\frac{8\times6+12\times9}{300}=\frac{156}{300}=\frac{39}{75}\)

42.

Write all three-digit numbers that can be written using the digits 3, 6, 8 without repeating the digits.

Answer»

Answer is 368, 386, 683, 638, 836, 863

43.

A bag contains 10 blue balls and 12 yellow balls. Another contains 15 blue balls and 7 yellow balls. a. What is the probability of getting a yellow ball from the first bag? b. What is the probability of getting a yellow ball from the second bag? C. If all the balls are put in a single bag, what is the probability of getting a yellow ball from it?

Answer»

a. Total number of balls in the first bag = 10 + 12 =22, Number of yellow balls = 12

Probability of getting a yellow ball = \(\frac{12}{22}=\frac{6}{11}\)

b. Total number of balls in the second bag = 15 + 7 = 22, Number of a yellow ball = 7

Probability of getting a yellow ball = \(\frac{7}{22}\)

c. Total number of balls = 22 + 22 = 44 Number of yellow balls = 12 + 7 = 19

Probability of getting a yellow ball = \(\frac{19}{44}\)

44.

Each two-digit number is written on a paper slip and these are all put in a box. What is the probability that the product of the digits of a number drawn is a prime number? What if three-digit numbers are used instead?

Answer»

Total two-digit numbers = 90 

Product of the digits of a number drawn is a prime number 12, 13, 15, 17, 21, 31, 51, 71. 

(1 is not a prime number)

Total number whose product of the digits drawn is a prime number = 8 

Probability of product of the digits drawn is a prime number = \(\frac{8}{90}=\frac{4}{45}\)

Total three-digit numbers = 900 

Product of the digits of a number drawn is a prime number 112, 113, 115, 117, 121, 131, 151, 171, 211, 311, 511, 711.

Total number whose product of the digits drawn is a prime number = 12

Probability of product of the digits drawn is a prime number = \(\frac{12}{900}=\frac{4}{300} =\frac{1}{75}\)

45.

One is asked to say a two-digit number. What is the probability of it being a perfect square?

Answer»

Total no. of two-digit numbers = 90

Perfect squares from 10 to 99 are 16, 25, 36, 49, 64, 81.

There are 6 favourable numbers Probability = \(\frac{6}{90}=\frac{1}{15}\)

46.

A box contains four slips numbers 1, 2, 3, 4 and another contains three slips numbered 1, 2, 3. If one slip is taken from each, what is the probability of the product being odd? The probability of the product being even?

Answer»
First boxSecond boxProduct
111
122
133
212
224
236
313
326
339
414
428
4312

Probability of sum being odd = \(\frac{4}{12}=\frac{1}{3}\)

Probability of sum being even = \(\frac{8}{12}=\frac{2}{3}\)

47.

Numbers from 1 to 50 are written on slips of paper and put in a box. A slip is to be drawn from it; but before doing so, one must make a guess about the number, either prime number or a multiple of five. Which is the better guess? Why?

Answer»

Probablity of getting prime numbers from 1 to 50 = \(\frac{15}{50}=\frac{3}{10}\)

Probability of getting a multiple of 5 from 1 to 50 = \(\frac{10}{50}=\frac{1}{5}\)

∴ Better guess would be prime numbers as probability of that is more.

48.

Y=sinx/1+cosx

Answer»
cosx-cos2x/(1-cosx)^2
use u/v rule and answer will come for sure and ans is 1/1+cosx
49.

(d) \( \int \frac{x-1}{\sqrt{x^{2}+1}} d x \)

Answer»

x=tany 

int (tanysecy -sec y)dy

sec y- ln(sec y+ tan y)

50.

What is mean by quadratic equation

Answer»

A quadratic equation as an equation of degree 2, meaning that the highest exponent of this function is 2. The standard form of a quadratic is y = ax2 + bx + c, where a, b, and c are numbers and a cannot be 0. Examples of quadratic equations include all of these: y = x2 + 3x + 1.