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.

Solve 24x lt100 , when x is a natural number.

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ANSWER :{1,2,3,4}
2.

Integrate the function (4x+1)/(sqrt(2x^(2)+x-3))

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ANSWER :`2sqrt(2X^(2)+x-3)+C`
3.

SetA,B,C, A cap B, A cap B, Acap C, B cap C and A cap B cap Chave 35, 40, 45, 13, 12, 14 and 5 elements respectively. An element is selected at random from the set a cup V cup C . The probability thatthe selected elementbelongs to only set A is

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`(13)/(86)`
`(35)/(86)`
`(5)/(86)`
`(15)/(86)`

ANSWER :D
4.

Let f : [1/2, 1] to R (the set of all real numbers) be a positive, non -constant and differentiable function such that the f'(x) < 2 f(x) and f(1/2) = 1. Then the value of int_(1//2)^(1) f(x) dx lies in the interval :

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`(2e - 1, 2e)`
`(E - 1, 2e - 1)`
`((e - 1)/(2), e - 1)`
`(0,(e - 1)/(2))`

ANSWER :D
5.

1.5 ml of the gaseous hydrocarbonrequired 375 ml of air (containing 20% O_(2) by volume) for complete combustion. The resultantgaseous mixture occupied 345 ml. The formula of the hyrocarbonis

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`C_(4)H_(8)`
`C_(3)H_(8)`
`C_(3)H_(4)`
`C_(2)H_(4)`

ANSWER :B
6.

If the normal at (1,2) on the parabola y^(2)=4x meets the parabola again at the point (t^(2),2t) then the value of t is

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1
3
`-3`
1

Answer :C
7.

Evaluate (ii) int_(a)^(b) sqrt((x-a)/(b-x))dx (a lt x lt b)

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ANSWER :`pi/2 (a-b)`
8.

A function f: R rarr R satisfies the equation f(x+ y)= f(x).f(y) "for all" x, y in R, f(x) ne 0. Suppose that the function is differentiable at x=0 and f'(0)=2, then prove that f'(x)= 2f(x)

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ANSWER :`F'(X)= 2 f(x)`
9.

Two gases N_(2)and H_(2) are allowed to react from mixture of N_(2)H_(2)(1) and N_(2)H_(4)(g) leaving none of the reactants. Formation of N_(2)H_(2) (1) does not create any energy change whereas formation of 1 ml N_(2)H_(4)(g) absorbs 2 Joule energy. Ratio of volume contraction to energy change (in ml/Joule) during reaction when 30 ml N_(2)and 40 ml H_(2) react under similar conditions of temperature and pressure.

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Solution :`N_(2)+H_(2)toN_(2)H_(2)(1)+N_(2)H_(4)(g)`
`POAC on H ""a ML""bml`
`30xx2=2a+2bimpliesa+b=30`
`POAC on H40xx2=2a+4bimpliesa+2b=30`
`b=10,a=20`
`V.C.=(30+40)-10=60ml`
Energy change `=10xx2=20`
`(V.C.)/("Energy change")=(60)/(20)=3`
10.

Solve the following systems of linear inequalities graphically : x lt y, x gt 0 , y lt 1.

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Solution :`x LT y`
`x gt 0`
`y lt 1`

Step - Let US CONSIDER the POINT (1,0) that does not lie on these lines. Putting x = 0 , y = 0 in the inequations we get clearly (1,0) satisfies x`gt`0, y `lt` 1 but does not satisfy x `lt` y.
`therefore` The shaded region is the solution region.
11.

The solution vectors vecr of the equation vecr xx hati=hatj+hatk and vecr xx hatj=hatk+hatj represent two straight lines which are :

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INTERSECTING
NON COPLANAR
Coplanar
Non intersecting

ANSWER :B::D
12.

If P(A)= (2)/(5), P(B)= (3)/(10) and P(A cap B)= (1)/(5) , then P(A'//B') * P(B'//A') is equal to ……….

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`(5)/(6)`
`(5)/(7)`
`(25)/(42)`
1

Answer :C
13.

If (0,-3) is one limiting point of a coaxal system of circlesx^(2) + y^(2) + 4y + 7 = 0is a member , then the other limiting point is

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(-2,-2)
(2,1)
(6,5)
(5,3)

ANSWER :A
14.

Find (dy)/(dx) of the functions given in Exercises 12 to 15. xy= e^((x-y)).

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ANSWER :`(y(X-1))/(x(y+ 1))`
15.

Let vec(a)=hati+hatj+hatk,vec(b)=hati and vec( c )=c_(1)hati+c_(2)hatj+c_(3)hatk. Then If c_(1)=1 and c_(2)=2 find c_(3) which makes vec(a),vec(b) and vec( c ) coplanar.

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ANSWER :`:.-c_(3)+2=0=>c_(3)=2`
16.

int_(0)^(pi)(x dx)/(1+sin x)

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Solution :`"Let I"= int_(0)^(pi) (x)/(1+sinx)DX`
`RARR ""I=int_(0)^(pi) (pi-x)/(1+sin (pi-x))dx`
`=int_(0)^(pi)(pi-x)/(1+sin x)dx`
Adding equations (1) and (2)
`2I =int_(0)^(pi)(x+pi-x)/(1+sin x)dx`
`=piint_(0)^(pi)(1)/(1+sinx).(1-sin x)/(1-sin x)dx`
`=piint_(0)^(pi)(1-sinx)/(1-sin^(2)x)dx`
`=pi int_(0)^(pi)(1-sinx)/(COS^(2)x)dx`
`=pi int_(0)^(pi)(sec^(2)x-secx tan x) dx`
`=pi [tan x-sec x]_(0)^(pi)`
`=pi [(tan pi-sec pi)-(tan 0-sec 0)]`
` =pi (1+1) =2pi`
`rArr ""I=pi`
17.

int(logx+(1)/(x^(2)))e^(x)dx=..........+c

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`e^(x)(logx+(1)/(x^(2)))`
`e^(x)(logx+(1)/(x))`
`e^(x)(logx-(1)/(x^(2)))`
`e^(x)(logx-(1)/(x))`

ANSWER :D
18.

Match thefollowing .

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a,B,C,d
b,c,a,d
c,d,b,a
d,c,b,a

Answer :D
19.

The slopes of the lines given by 12x^(2)+bxy-y^(2)=0 differ by 6, Then value of b is

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`2`
`PM2`
`pm1`
`1`

ANSWER :C
20.

We know that , ifa_(1),a_(2),….a_(n) are in A.P and vice versa . If a_(1),a_(2),…a_(n)are in A.P and viceversa . If a_(1),a_(2)….a_(n) are in A.Pwith common difference d, then for nay b ( gt 0) the numbersb^(a_(1)),b^(a_(2)),b^(a_(3)),....,b^(a_(n)) are in G.Pwith commonratio b^(d) If a_(1),a_(2),.....a_(n) are positive and in G.P with common ratio r , then for any base b(b gt 0), log_(b) a_(1) , log _(b) a_(2) , ..., log_(b) a_(n) are in A.P with common differencelog_(b)r If p,q,r are in A.P , then the pth , the qth , therth terms of any G.P are in

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A.P
G.P
H.P
A.G.P

Answer :B
21.

Two events E and F are independent. If P(E ) = 0.3and P(E cup F)= 0.5 ,then P(E//F)- P(F//E) equal ………

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`(2)/(7)`
`(3)/(35)`
`(1)/(70)`
`(1)/(7)`

Answer :C
22.

Consider a triangle ABC with sides AB and AC having the equations L_1 = 0 and L_2 = 0 . Let the centroid, orthocentre and circumcentre of the Delta ABCare G, H and S respectively. L = 0 denotes the equation of side BC. If L_1 : x+y – 1=0 and L_2 : 2x – y + 4=0and S(2, 1) then find the x-intercept of the line L = 0.

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ANSWER :`3/2`
23.

We know that , ifa_(1),a_(2),….a_(n) are in A.P and vice versa . If a_(1),a_(2),…a_(n)are in A.P and viceversa . If a_(1),a_(2)….a_(n) are in A.Pwith common difference d, then for nay(b gt 0) the numbersb^(a_(1)),b^(a_(2)),b^(a_(3)),....,b^(a_(n)) are in G.Pwith commonratio b^(d) If a_(1),a_(2),.....a_(n) are positive and in G.P with common ratio r , then for any base b(b gt 0), log_(b) a_(1) , log _(b) a_(2) , ..., log_(b) a_(n) are in A.P with common differencelog_(b)r If a,b,c,d are in G.P and a^(x) = b^(y) = c^(z) = d^(v) , then x, y , z , v are in

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A.P
G.P
H.P
None of these

ANSWER :C
24.

int_(0)^(1) (x-1) e^(-x) dx=

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`- 1/e`
`1/e`
e
2e

Answer :A
25.

We know that , ifa_(1),a_(2),….a_(n) are in A.P and vice versa . If a_(1),a_(2),…a_(n)are in A.P and viceversa . If a_(1),a_(2)….a_(n) are in A.Pwith common difference d, then for nay b ( gt 0) the numbersb^(a_(1)),b^(a_(2)),b^(a_(3)),....,b^(a_(n)) are in G.Pwith commonratio b^(d) If a_(1),a_(2),.....a_(n) are positive and in G.P with common ratio r , then for any base b(b gt 0), log_(b) a_(1) , log _(b) a_(2) , ..., log_(b) a_(n) are in A.P with common differencelog_(b)r Ifx, y , zare respectively the pth , qth and the rthtermsof an A.P ..., A.P.., as well as of a G.P , then x^(y-z),y^(z-x).z^(x-y) is equal to

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p
q
r
1

Answer :D
26.

Find the condition that x^3-px^2+qx-r=0 may have the roots in G.P .

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ANSWER :`p^3 r=q^3`
27.

Two balls are drawn at random with replacement from a box containing 10 black and 8 red balls. Find the probability that (i) both balls are red. (ii) first ball is black and second is red. (iii) one of them is black and other is red.

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ANSWER :(i) `(16)/(81)`, (II) `(20)/(81)`, (iii) `(40)/(81)`
28.

If f: R to R, g: R to R and h: R to R is such that f(x)=x^(2), g(x)= tan x and h (x)= logx then the value of [ho (gof)]x , if x=(sqrt(pi))/(2) will be

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0
1
`-1`
10

Answer :A
29.

Consider a triangle ABC with sides AB and AC having the equations L_1 = 0 and L_2 = 0 . Let the centroid, orthocentre and circumcentre of the Delta ABCare G, H and S respectively. L = 0 denotes the equation of side BC. If L_1 : 2x + y = 0 and L_2 : x – y + 2 = 0and H(2, 3) then find the y-intercept of L = 0.

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ANSWER :2
30.

If the position vectors of the points A,B,C are -2bar(i)+bar(j)-bar(k), -4bar(i)+2bar(j)+2bar(k), 6bar(i)-3bar(j)-13bar(k) respectively and bar(AB) = lambda bar(AC) then find the value of lambda.

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ANSWER :`-(1)/(4)`
31.

Evaluation of definite integrals by subsitiution and properties of its : f(x)=|(sinx+sin2x+sin3x,sin2x,sin3x),(3+4sinx,3,4sinx),(1+sinx,sinx,1)| then int_(0)^(pi/2)f(x)dx=……….

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3
`(2)/(3)`
`(1)/(3)`
0

Answer :C
32.

Show that the vectors bar(a) = 2 hat(i) - 3 hat(j) + 4 hat(k) and bar(b) = -4 hat(i) + 6 hat(j) - 8k are collinear.

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ANSWER :`BAR(B) = -2 HAT(a)`
33.

The straight line x + y + 1 = 0 bisects an angle between a pair of lines, of which one is 2x - 3y + 4 = 0 . Then the equation of the other line in that pair is

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2x + 3Y + 4 = 0
X - y + 1 = 0
5x - 5y + 9 =0
3X - 2Y + 5 = 0

Answer :D
34.

Consider the integral int_(-2)^(2) (dx)/(4 + x^(2)) . Itis easy to conclude that it is equal to (pi)/(4) .Indeed int_(-2)^(2) (dx)/(4 + x^(2)) = (1)/(2) "arc tan "(x)/(2) |_(-2)^(2)= (1)/(2) [(pi)/(4) - (-(pi)/(4))]= (pi)/(4)On the other hand, making the substitution x = (1)/(t) we havedx = - (dt)/(t^(2))|{:(x," "t),(-2,-1//2),(2,1//2):}| int_(-2)^(2) (dx)/( 4 + x^(2)) = - int_(-1//2)^(1//2) (dt)/(t^(2)(4 + (1)/(t^(2))))= - int _(-1//2)^(+1//2) (dt)/(4t^(2) + 1)=(1)/(2) "arc tan 2t |_((1)/(2))^((1)/(2)) = - (pi)/(4) This result is obviously wrong, since the integrand (1)/(4 + x^(2)) gt0 , andconsequently, thedefinite integral of this function cannot be equal to a negative number -(pi)/(4) . Find the mistake .

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Answer :The SUBSTITUTION`X = (1)/(t)` will not do, since THISFUNCTION is descontinuous at t = 0
35.

Let g be the inverse function of f and f '(x) = (x^(10))/(1+x^(2)) if g(2) = a then g'(2) is equal to:

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`(a)/(2^(10))`
`(1+a^(2))/(a^(10))`
`(a^(10))/(1+a^(2))`
`(1+a^(10))/(a^(2))`

SOLUTION :`f(g(x))=x`
`RARR f'(g(x)).g'(x)=1`
`rArr g'(x)=(1)/(f'(g(x)))=(1+(g(x))^(2))/((g(x))^(10))`
`rArr g'(2)=(1+(g(2))^(2))/((g(2))^(10))`
36.

Area of the triangle is calculated by the formula A=(1)/(2)ab sin C. If C = (pi)/(6) and error in the measure of C is x%, find the approximate change in the area of the triangle. Where a and b are constant.

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ANSWER :`(sqrt(3)PI X)/(6)%`
37.

If the equation x^(2)-cx+d=0 has roots equal to the fourth powers of the roots of x^(2)+ax+b=0, where a^(2)gt4b, then the roots of x^(2)-4bx+2b^(2)-c=0 will be

Answer»

both REAL
both negative
both POSITIVE
ONE positive and one negative

Answer :A::D
38.

Integrate the following rational functions : int(dx)/(x(x+2))

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Answer :`(1)/(2)LOG|(X)/(x+2)|+C`
39.

Find the mean deviation about mean of first 2n+1 natural numbers from mean.

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ANSWER :`(N(n+1))/(2n+1)`
40.

Find the equation of the circle with centre (-3, 4)and touching y-axis.

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Answer :`X^(2) + y^(2)+6x -8Y +16 =0`
41.

Sho that 3/6 + (3.5)/(6.9) + (3.5.7)/(6.9.12)+ ……..oo 3 sqrt3 - 4

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ANSWER :`3 SQRT3 - 4`
42.

Prove that if (a + b+ c)(b + c - a) = 3bc then A = 60^@

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SOLUTION :(a + B + c)(b + c + a) =3bc
or, ab + ca - a^2 + b^2 + BC - ab + bc + c^2 - ca = 3bc`
or, `b^2 + c^2 -a^2 = bc`
or, `(b^2 + c^2 - a^2)/(2bc) = 1/2`
or, COSA = 1/2 or , A = `60^@`
43.

If the lines L_1 and L_2in space are defined by L_1 = {x=sqrt lambda y+ (lambda-1) z= (sqrtlamda -1) y+sqrtlambda ) and L_2 ={ x=sqrtmu y + (1-sqrtmu ), z =(1-sqrtmu )y +sqrtmu )thenL_ 1is perpendicular to L_2 for all non- negative realslambda and musuch that

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` sqrtlambda +SQRT mu =1`
` lambda NE mu `
` lambda +mu =0 `
`lambda = mu`

ANSWER :D
44.

For any positive integers m, n (with n ge m) If ({:(n),(m):}) = .^(n)C_(m) Prove that ({:(n),(m):}) + ({:(n - 1),(m):}) + ({:(n - 2),(m):}) + … + ({:(m),(m):}) = ({:(n + 1),(m + 1):}) Prove that ({:(n),(m):}) + 2 ({:(n + 1),(m):}) + 3 ({:(n - 2),(m):}) + .... + (n - m + 1) ({:(m),(m):}) = ({:(n + 2),(m + 2):})

Answer»

Solution : Let `S = ((n)/(m))+((n-1)/(m)) + ((n-2)/(m))+ ((n-2)/(m)) +.....+((m)/(m)) =((n+1)/(m+1)).....(i)`
It is obvious that, `n ge m`
Note : Thisquestion is based UPON additive loop.
Now ,`S =((m)/(m)) + ((m+1)/(m)) + ((m+2)/(m)) +.......+((n)/(m))`
` ={((m+1)/(m+1))+((m+1)/(m))}[because ((m)/(m)) = 1= ((m+1)/(m+1))]`
`= ((m+2)/(m+1)) + ((m+2))/(m)) + ......+ ((n)/(m))""[because""^(n)C_(R)+ ""^(n)C_(r+1) = ""^(n+1)C_(r+1)]`
`=((m+2)/(m+1)) +......+((n)/(m))`
`=.............`
` =((n)/(m+1))+((n)/(m)) = ((n+1)/(m+1))` whichis ture....(ii)
Again, we haveto prove that
`((n)/(m))+2((n-1)/(m)) + 3((n-2)/(m)) +......+ (n-m+1)((m)/(m)) = ((m+2)/(m+2))`
Let`S_(1) = ((n)/(m))+2((n-1)/(m)) +3((n-2)/(m)) +......+(n-m+1)((mm)/(m))`
`{:(= ((n)/(m)) + ((n-1)/(m)) + ((n-2)/(m)) +...+ ((m)/(m))), ( ""+ ((n-1)/(m)) + ((n-2)/(m)) +...+ ((m)/(m))), (""+ ((n-2)/(m)) +...+((m)/(m)) ),(""...) , (""+ ((m)/(m))):}}n-m + 1` rows
Now, SUM of the first row is `((n+1)/(m+1))`
Sum of the second row is `((n)/(m+1))`
Sumof thethird row is `((n+1)/(m+1))`,
....................
Sum of the last row is `((m)/(m)) = ((m+1)/(m+1))`
THUS `S = ((n+1)/(m+1))+((n)/(m+1)) + ((n +1)/(m+1))+.......+ ((m+1)/(m+1)) = ((n+1+1)/(m+2)) = ((n+2)/(m+2))`
[from Eq. (i) replacing nbyn +1 and m by m + 1]
45.

Leta ne 0and p(x )be apolynomialof degreegreaterthan2.If P(x )leavesremaindera and-awhendividedrespectivelybyx+aand x-athentheremainderwhenp(X )isdividedbyx^2 -a^2 is

Answer»

2X
`-2x`
`X`
`-x`

ANSWER :D
46.

Evaluate int x^(2) tan^(-1) x dx

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Answer :`(X^(3))/(3) tan^(-1) x - (x^(2) )/(6) + (1)/(6) LOG"" | 1 + x^(2)| + C`
47.

Find Order and Degree of given differential equation ((ds)/(dt))^(4) + 3s(d^(2)s)/(dt^(2)) = 0

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ANSWER :ORDER 2; DEGREE 1
48.

What are the coordinates of the point P in the xy-plane that divides the line segment whose endpoints are A(-2, 9) and B(7, 3) into two segments such that the ratio of AP to PB is 1 to 2?

Answer»

<P>`P(1, 5)`
`P(4, 1)`
`P(1, 7)`
`P(2, 6)`

Answer :C
49.

If lim_(x rarr 0) (1+px)^(q//x) = e^(4), where p, q, in N, then :

Answer»

<P>p = 4, q = 2
p = 8, q = 4
p = 16, q = 8
None of these

Answer :D
50.

Evalute the following integrals int (x + 1)/(x^(2) + 3x + 12) dx

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Answer :`(1)/(2) log |x^(2) + 3x + 12 | - (1)/(SQRT(39)) tan^(-1) ((2x+ 3)/(sqrt(39)))+ x `