Number Series: Bank Exams (SBI, IBPS, RRB)

Q.1 Find tne next number: 3, 6, 15, 42, 123, ?

Check Solution

Ans: C

Explanation: The pattern is as follows: (previous number * 3) + (a number counting up from -3).
* 3*3 – 3 = 6
* 6*3 – 3 = 15
* 15*3 – 3 = 42
* 42*3 – 3 = 123
* 123*3 – 3 = 366

Q.2 Find the missing number in the given series:5, 12, 26, 54, 110, ?

Check Solution

Ans: C

Explanation: The pattern in the series is as follows:
* 12 = (5 * 2) + 2
* 26 = (12 * 2) + 2
* 54 = (26 * 2) + 2
* 110 = (54 * 2) + 2
Therefore, the next number in the series will be:
* ? = (110 * 2) + 2 = 222

Q.3 Find the missing number in the sequence: 25, 44, 66, 91, 119, ?

Check Solution

Ans: D

Explanation: The differences between consecutive numbers in the sequence are: 19, 22, 25, 28. The differences between these differences are constant at 3. Following this pattern, the next difference should be 28 + 3 = 31. Therefore, the missing number is 119 + 31 = 150.
Correct Option: D

Q.4 Find the missing number in the sequence: 4, 5, 12, 39, 160, ?

Check Solution

Ans: B

Explanation: The pattern is as follows:
4 * 1 + 1 = 5
5 * 2 + 2 = 12
12 * 3 + 3 = 39
39 * 4 + 4 = 160
160 * 5 + 5 = 805
Correct Option: B

Q.5 Find the missing number in the sequence: 40, 20, 20, 30, 60, ?

Check Solution

Ans: C

Explanation: The pattern is as follows:
* 40 / 2 = 20
* 20 * 1 = 20
* 20 * 1.5 = 30
* 30 * 2 = 60
* 60 * 2.5 = 150

Correct Option: C

Q.6 Find the missing number in the sequence: 6, 5, 9, 26, ?, 514

Check Solution

Ans: D

Explanation: The pattern is as follows:
* 6 -> 6 * 1 – 1 = 5
* 5 -> 5 * 2 – 1 = 9
* 9 -> 9 * 3 – 1 = 26
* 26 -> 26 * 4 – 1 = 103
* 103 -> 103 * 5 – 1 = 514
Correct Option: D

Q.7 What number should replace the question mark in the following series: 3, 7, 15, 31, ?, 127, 255

Check Solution

Ans: E

Explanation: The pattern in the series is: each number is obtained by multiplying the previous number by 2 and then adding 1.

3 * 2 + 1 = 7
7 * 2 + 1 = 15
15 * 2 + 1 = 31
31 * 2 + 1 = 63
63 * 2 + 1 = 127
127 * 2 + 1 = 255

Q.8 What should come in place of the question mark ‘?’ in the following number series: 11, 23, 47, 95, ?, 383

Check Solution

Ans: D

Explanation: The pattern in the series is as follows:
11 * 2 + 1 = 23
23 * 2 + 1 = 47
47 * 2 + 1 = 95
95 * 2 + 1 = 191
191 * 2 + 1 = 383

Q. 9 In the following number series, a wrong number is given. Find out the wrong number: 7, 14, 42, 168, 840, 5040, 30200

Check Solution

Ans: D

Explanation: The pattern in the series is as follows: 7 * 2 = 14, 14 * 3 = 42, 42 * 4 = 168, 168 * 5 = 840, 840 * 6 = 5040, 5040 * 7 = 35280. The wrong number is 30200, which should be 35280.

Next Chapter: Number systems

Practice: Bank Exam Questions (SBI, IBPS, RRB PO & Clerk)