# Aptitude Questions: Number Series Set 20

Hello Aspirants. Welcome to Online Quantitative Aptitude Section in AffairsCloud.com. Here we are creating question sample in Number Series, which is common for all the competitive exams. We have included Some questions that are repeatedly asked in bank exams !!!

1. 686, 438, 314, 252, 221, ?
A) 180
B) 187.5
C) 201
D) 205.5
E) 175.5
D) 205.5
Explanation:

686 – 248 = 438
438 – (248/2) = 438 – 124 = 314
314 – (124/2) = 314 – 62 = 252
252 – (62/2) = 252 – 31 = 221

2. 427, 85.4, 34.16, 20.496, ?
A) 14.3782
B) 16.2902
C) 16.3968
D) 20.3984
E) 11.6248
C) 16.3968
Explanation:

*0.2, *0.4, *0.6, *0.8

3. 6, 6, 4, 8, 3.2, 9.6, ?
A) 5.4
B) 2.8
C) 2.5
D) 4.1
E) None of these
B) 2.8
Explanation:

*1, ÷1.5, *2, ÷2.5, *3, ÷3.5

4. 4.2, 2.6, 2.1, 1.3, 1.05, 0.65, 0.525, ?
A) 0.315
B) 0.325
C) 0.435
D) 0.465
E) 0.535
B) 0.325
Explanation:

It is a double series:
÷0.5 :– 4.2, 2.1, 1.05, 0.525
÷0.5 :– 2.6, 1.3, 0.65, ?

5. 5, 9, 36, 208, 1398, ?
A) 7392
B) 14378
C) 12542
D) 6448
E) 11472
E) 11472
Explanation:

[5+22] × 1 = 9
[9+32] × 2 = 36
[36+42] × 4 = 208
[208+52] × 6 = 1398
[1398+62] × 8 = 11472

6. 4, 3, 12, 6, 36, 9, 108, 12, ?
A) 324
B) 252
C) 156
D) 182
E) 236
A) 324
Explanation:

It is a double series.
*3 :– 4, 12, 36, 108
+3 :– 3, 6, 9, 12

7. 2, 7, 29, 85, 192, ?
A) 385
B) 213
C) 264
D) 367
E) None of these
D) 367
Explanation:

It is a double difference series:
7-2 = 5, 29-7 = 22, 85-29 = 56, 192-85 = 107
22-5 = 17, 56-22 = 34, 107-56 = 51
So next [(51+17)+107]+192

8. 15, 27, 44, 66, 93, ?
A) 136
B) 125
C) 154
D) 165
E) 193
B) 125
Explanation:

15 + 12 = 27
27 + (12+5) = 27 + 17 = 44
44 + (17+5) = 44 + 22 = 66
66 + (22+5) = 93

9. 120, 170, 224, 280, 360, ?
A) 392
B) 442
C) 458
D) 528
E) 540
B) 442
Explanation:

11^2 – 1 = 120
13^2 + 1 = 170
15^2 – 1 = 224
17^2 + 1 = 280
19^2 – 1 = 360
21^2 + 1 = 442

10. 9, 9, 18, 54, 162, 324, ?
A) 428
B) 404
C) 386
D) 422
E) None of these
E) None of these
Explanation:

*1, *2, *3, *3, *2, *1

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