Number Series Questions and Answers Part-15

1. Find the missing term: 1, 1, 2, 6, 24, ?, 720
a) 100
b) 104
c) 108
d) 120

Answer: d
Explanation: The pattern is × 1, × 2, × 3, × 4, .............
So, missing term = 24 × 5 = 120

2.Find the missing term: 3, 10, 101, ?
a) 10101
b) 10201
c) 10202
d) 11012

Answer: c
Explanation: Each term in the series is obtained by adding 1 to the square of the preceding term.
So, missing term = (101)2 + 1 = 10202

3. Find the missing term: 5824, 5242, ?, 4247, 3823
a) 4467
b) 4718
c) 4856
d) 5164

Answer: b
Explanation: Each term in the series is obtained by subtracting from the preceding term the number formed by the first three digits of the preceding term,
So, missing term = 5242 - 524 = 4718

4. Find the missing term: 3, 8, 13, 24, 41, ?
a) 70
b) 75
c) 80
d) 85

Answer: a
Explanation: The pattern followed is:
n the term + (n + 1)th term + (n + 1) = (n + 2)th term
Thus, 1st term + 2nd term + 2 = 3rd term;
2nd term + 3rd term + 3 = 4th term and so on.
So, missing term = 6th term = 4th term + 5th term + 5 = 24 + 41 + 5 = 70

5. Find the missing term: 589654237, 89654237, 8965423, 965423, ?
a) 58965
b) 65423
c) 89654
d) 96542

Answer: d
Explanation: The digits are removed one by one from the beginning and the end in order alternately so as to obtain the subsequent terms of the series.

6. Find out the wrong term: 8, 14, 26, 48, 98, 194, 386
a) 14
b) 48
c) 98
d) 194

Answer: b
Explanation: The correct pattern is × 2, - 2.......
So, 48 is wrong and must be replaced by (26 × 2 - 2) i.e., 50.

7. Find out the wrong term: 8, 13, 21, 32, 47, 63, 83
a) 13
b) 21
c) 32
d) 47

Answer: d
Explanation: The correct pattern is + 5, + 8, + 11, + 14, ............
So, 47 is wrong and must be replaced by (32 + 14) i.e., 46

8. Find out the wrong term: 10, 26, 74, 218, 654, 1946, 5834
a) 26
b) 74
c) 218
d) 654

Answer: d
Explanation:
So, 654 is wrong and must be replaced by (218 × 3 - 4) i.e., 650.

9.Find out the wrong term: 4, 10, 22, 46, 96, 190, 382
a) 4
b) 10
c) 96
d) 382

Answer: c
Explanation: The correct pattern is + 6, + 12, + 24, + 48, + 96, + 192 ............
So, 96 is wrong and must be replaced by (46 + 48) i.e., 94

10. Find out the wrong term: 1, 3, 10, 21, 64, 129, 356, 777
a) 21
b) 129
c) 10
d) 356

Answer: d
Explanation: The correct pattern is × 2 + 1, × 3 + 1, × 2 + 1, × 3 + 1,...........
So, 356 is wrong and must be replaced by (129 × 3 + 1) i.e., 388.