Expected Number Series Questions for IBPS PO Mains(Exam Based)

Directions (1-10): What value should come in place of question-mark (?) in the following number series?

Ques 1.

21, 142, 286, 455, 651, ?

1. 878
2. 786
3. 867
4. 876
5. 875

 4;

The series is + 11², + 12², + 13², + 14²,...............

∴ ? = 651 + 15² = 651 + 225 = 876

Ques 2.

1, 9, 76, 765, 9186, ?
1. 128611
2. 128116
3. 12611
4. 128600
5. 126118

1;

The series is x6+3, x8+4, x10+5, x12+6, ..............

∴ ? = 9186 x 14+7 = 128611

Ques 3.

24, 43, 81, 138, 214, ?
1. 380
2. 309
3. 308
4. 390
5. 328

2;

The series is +19, +38, +57, +76, ...........

∴ ? = 214 + 95 = 309

Ques 4.

31, 16, 9, 6, 5, 5, ?
1. 4.5
2. 2.5
3. 4
4. 3.5
5. 5.5

5;

The series is +1÷ 2, +2÷2, +3÷2, +4÷2, +5÷2, +6÷2.......

∴ ? = 5+6 ÷ 2 = 5.5

Ques 5.

8, 9, 20, 63, 250, 1285
1. 20
2. 63
3. 250
4. 9
5. 1285

3;

The series is 

Hence there should be 256 in place of 250.

Ques 6.

6, 15, 37, 53, 178, 214
1. 15
2. 37
3. 214
4. 53
5. 178

1; 

Their series is 

Hence there should be 10 in place of 15.

Ques 7.

11, 5, 3, 4.5, 7, 15
1. 5
2. 11
3. 4.5
4. 7
5. 3

5; 

The series is 

Hence there should be 4 in place of 4.5

Ques 8.

5, 31, 159, 645, 1951, 3825
1. 31
2. 3825
3. 1951
4. 159
5. 645

2;

The series is 

Hence there should be 3927 in place of 3825.

Ques 9.

30, 29, 50, 128, 428, 2015
1. 50
2. 29
3. 30
4. 128
5. 428

4; 

The series is 

Hence there should be 123 in place of 128.

Ques 10.

4;