## Number Series Questions and Answers Part-12

1. Find the missing number:- 0.5, 0.55, 0.65, 0.8, ?
a) 0.9
b) 0.82
c) 1
d) 0.95

Answer: c
Explanation: The pattern is + 0.05, + 0.10, + 0.15,................
So, missing term = 0.8 + 0.20 = 1

2. Find the missing term: 9, 27, 31, 155, 161, 1127, ?
a) 316
b) 1135
c) 1288
d) 2254

Answer: b
Explanation: The pattern is × 3, + 4, × 5, + 6, × 7,
So, missing term = 1127 + 8 =1135

3. Find the missing term: 5, 6, 9, 15, ?, 40
a) 21
b) 25
c) 27
d) 33

Answer: b
Explanation: The pattern is + 1, + 3, + 6, ............i.e., + 1, + (1 + 2) + (1 + 2 + 3)...............
So, missing term = 15 + (1 + 2 +3 +4) = 25

4. Find the missing term :- 3, 15, ?, 63, 99, 143
a) 27
b) 35
c) 45
d) 56

Answer: b
Explanation: The terms of the given series are (22 - 1), (42 - 1),................,(82 - 1), (102 - 1), (122 - 1)
So, missing term = (62 - 1) = (36 - 1) = 35

5. Find the missing term: 2, 3, 5, 7, 11, ?, 17
a) 12
b) 13
c) 14
d) 15

Answer: b
Explanation: Clearly, the given series consists of prime numbers starting from 2. So, the missing term is the prime number after 11, which is 13.

6. Which term of the series 5,10, 20, 40,...................is 1280 ?
a) 10th
b) 9th
c) 8th
d) None of these

Answer: b
Explanation: Clearly, 5 × 2 = 10, 10 × 2 =20, 20 × 2 = 40,.............................
So, the series is G.P. in which a = 5 and r = 2.
Let 1280 be the nth term of the series.
Then, 5 × 2n - 1= 1280 ⇔2n - 1= 256 = 28 ⇔ n - 1 = 8 ⇔ n = 9

7. Find the missing term: 0, 2, 3, 5, 8, 10, 15, 17, 24, 26, ?
a) 28
b) 30
c) 32
d) 35

Answer: d
Explanation: The given sequence is a combination of two series:
I. 0, 3, 8, 15, 24, ? and
II. 2, 5, 10, 17, 26
The pattern in each one of I and II is + 3, + 5, + 7, + 9,..............
So, missing term = 24 + 11 = 35

8. Find the missing term: 3, 10, 29, 66, 127, ?
a) 164
b) 187
c) 216
d) 218

Answer: d
Explanation: The given series is a triangular pattern series.
So, we have
3       10       29       66       127       ?
7       19       37       61
12        18      24
6           6
So, missing term
= 127 + (61 + 24 + 6)
= 127 + 91
= 218

9. Find the missing term: 13, 35, 57, 79, 911, ?
a) 1110
b) 1112
c) 1113
d) 1315

Answer: c
Explanation: The term of the given series are numbers formed by joining together consecutive odd numbers in order i.e., 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11...................
So, missing term = number formed by joining 11 and 13 = 1113

10. What will come at the place of question mark ?
2/3 , 4/7 , ? , 11/21 , 16/31
a) 5/9
b) 6/11
c) 7/13
d) 9/17

Answer: c
Explanation: The sequence in the numerators is + 2, + 3, + 4, + 5 and that in the denominators is + 4, + 6, + 8, + 10
So, the numerator of the missing fraction should be (4 + 3)i.e., 7 and the denominator should be (7 + 6)i.e., 13. Thus, the missing term is 7/13 .