11 + Interview Questions in AIRTHMETIC PROGRESSIONS IN GENERAL AWARENESS Page 1 InterviewSolution

1.	If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term will be(A) 7 (B) 11 (C) 18 (D) 0
Answer» Correct answer is (D) 0

2.	Which term of the AP: 21, 42, 63, 84,... is 210?(A) 9th (B) 10th (C) 11th (D) 12th
Answer» Correct answer is (B) 10^th

3.	Find four numbers in AP whose sum is 8 and the sum of whose squares is 216.
Answer» (4, 6, 8, 10) or (10, 8, 6, 4)

4.	Find the value of the middle most term (s) of the AP : –11, –7, –3,..., 49.
Answer» Solution : Here, a = –11, d = –7 – (–11) = 4, an = 49 We have an = a + (n – 1) d So, 49 = –11 + (n – 1) × 4 i.e., 60 = (n – 1) × 4 i.e., n = 16 As n is an even number, there will be two middle terms which are (16/2)^th and(16/2+1)^th i.e., the 8th term and 9th term. a₈= a + 7d = –11 + 7 × 4 = 17 a₉= a + 8d = –11 + 8 × 4 = 21 So, the values of the two middle most terms are 17 and 21, respectively.

4.

Find the value of the middle most term (s) of the AP : –11, –7, –3,..., 49.

Answer»

Solution :

Here, a = –11, d = –7 – (–11) = 4, an = 49

We have an = a + (n – 1) d

So, 49 = –11 + (n – 1) × 4

i.e., 60 = (n – 1) × 4

i.e., n = 16

As n is an even number, there will be two middle terms which are (16/2)^th and(16/2+1)^th

i.e., the 8th term and 9th term.

a₈= a + 7d = –11 + 7 × 4 = 17

a₉= a + 8d = –11 + 8 × 4 = 21

So, the values of the two middle most terms are 17 and 21, respectively.

5.	The sum of first five multiples of 3 is(A) 45 (B) 55 (C) 65 (D) 75
Answer» Correct answer is (A) 45

6.	Which of the following form an AP? Justify your answer.(i) –1, –1, –1, –1, ...(ii) 0, 2, 0, 2, ...(iii) 1, 1, 2, 2, 3, 3,...(iv) 11, 22, 33,...(v)1/2 ,1/3 ,1/4 , ...(vi) 2, 22, 23, 24, ...
Answer» (i), and(iv) form an AP as in each of these a_k-1 a_k is the same for different values of k.

7.	Two APs have the same common difference. The first term of one of these is–1 and that of the other is – 8. Then the difference between their 4th terms is(A) –1 (B) – 8 (C) 7 (D) –9
Answer» Correct answer is (C) 7

8.	In an AP, if a = 3.5, d = 0, n = 101, then an will be(A) 0 (B) 3.5 (C) 103.5 (D) 104.5
Answer» Correct answer is (B) 3.5

9.	The first four terms of an AP, whose first term is –2 and the common difference is –2, are(A) – 2, 0, 2, 4(B) – 2, 4, – 8, 16(C) – 2, – 4, – 6, – 8(D) – 2, – 4, – 8, –16
Answer» Correct answer is (C) – 2, – 4, – 6, – 8

10.	The sum of first 16 terms of the AP: 10, 6, 2,... is(A) –320 (B) 320 (C) –352 (D) –400
Answer» Correct answer is (A) –320

11.	The famous mathematician associated with finding the sum of the first 100 natural numbers is(A) Pythagoras (B) Newton(C) Gauss (D) Euclid
Answer» Correct answer is (C) Gauss