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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
   
   Answer & Explanation

   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
    
    Answer & Explanation

    E) None of these
    Explanation:
    *1, *2, *3, *3, *2, *1