NUMBER SERIES
Explanation: There are two series:
Ist : 17 14 11 8 and 2nd: 16 12 8 ?
In first series, -3 , -3 ,-3….. and in 2nd series , -4 , -4 ,-4….
Therefore, next term will be 8 – 4 = 4.
Explanation: 54+12, 66+16, 82+20, 102+24, 126, __. The difference is increasing by 4, starting with 12. So, the next difference is 24 + 4 = 28. Hence, the next number is 126 + 28 = 154.
9.3 2 2 5 5 5 7 8 8 9 11 11 ?
1. 12
2. 11
3. 9
4. 14
Sol: Option 2
Explanation: There are three parallel series going on in this question. The 1st, 4th, 7th terms are using logic of -1, 2nd, 5th and 8th terms are using logic of +1 and 3rd, 6th and 9th terms are using logic of +1 again. Answer will be 11, which belongs to 1st, 4th and 7th term.
10. 1 3 2 6 3 11 4 18 5 ?
1. 27
2. 25
3. 23
4. 29
Answer: Option 1
Explanation: CASE 1: 1+1=2 +1=3 +1=4 +1 =5, CASE 2: 3 +3=6 +5=11 +7= 18 +9=27
11. 13 17 23 29 31 37 ?
1. 22
2. 41
3. 19
4. 23
Sol: Option 2
Explanation: The given series is a prime number series. Hence the next prime number in this sequence would be 41.
12. 2 3 10 38 172 (Find the wrong no. in this series)
1. 192
2. 10
3. 38
4. 2
Answer: Option 3
Explanation: Logic is 2×1 + 1 = 3, 3 × 2 + 4 =10, 10 × 3 + 9 = 39, 39 × 4 + 16 = 172…. So in place of 38, it should be 39.
13. 8 19 52 151 447 (Find the wrong no. in this series)
1. 19
2. 8
3. 52
4. 447
Sol: Option 4
Explanation: The logic is 8 × 3 – 5 = 19, 19 × 3 – 5 = 52, 52 × 3 – 5 = 151. So in place of 447, it should be 448.
14. 4 2 3 7.5 26.75 (Find the wrong no. in this series)
1. 26.75
2. 7.5
3. 3
4. 2
Sol: Option 1
Explanation: Logic is 4 × .5 = 2, 2 × 1.5 = 3, 3 × 2.5 = 7.5, 7.5 × 3.5 = 26.25 In place of 26.75, it should be 26.25.
15. 2 3 10 40 172 885 5346 (Find the wrong no. in this series)
1. 3
2. 885
3. 40
4. 172
Sol: Option 3
Explanation: Logic is 2 × 1 + 1 = 3, 3 × 2 + 4 = 10, 10 × 3 + 9 = 39. Thus the wrong number is 40,it should be 39.
16. 15 18 20 29 45 70 106 (Find the wrong no. in this series)
1.18
2.20
3.29
4.45
Sol: Option 1
Explanation: Starting from the back
106– 70 = 36, 70- 45 = 25, 45 – 29 = 16, 29 – 20 = 9, 20 – 16 = 4, 16 – 15 = 1. Every difference is perfect square starting from 36 and decreasing. Thus the wrong number is 18, it should be 16.
17. 11 14 20 29 40 56 (Find the wrong no. in this series)
1. 40
2. 4
3. 10
4. 19
Sol: Option 1
Explanation: Logic is that first difference is 3, next difference is 6, 9, so next should be 12 & 15. So instead of 40 the term should be 41
18. 49 50 46 55 38 64 28 (Find the wrong no. in this series)
1. 49
2. 46
3. 55
4. 38
Sol: Option 4
Explanation: Logic is 49 + 1 = 50, 50 – 4 = 46, 46 + 9 = 55, 55 – 16 = 39, 39 + 25 = 64. Thus the wrong number is 38, it should be 39.
19. 6 15 41 179 839 (Find the wrong no. in this series)
1. 15
2. 6
3. 179
4. 41
Sol: Option 3
Explanation: Logic is 6 × 2 + 3 = 15, 15 × 3 – 4 = 41, 41 × 4 + 5 = 169, 169 × 5 – 6 = 839
Thus the wrong number is 179, it should be 169.
20. 4 6 12 30 90 312.50 1260 (Find the wrong no. in this series)
1. 6
2. 90
3. 30
4. 312.50
Sol: Option 4
Explanation: Logic is 4 × 1.5 = 6, 6 × 2 = 12, 12 × 2.5 = 30, 30 × 3 = 90, 90 × 3.5 = 315, 315 × 4 = 1260. Thus the wrong number is 312.50, it should be 315.
21. 35 19 11 7 5 4.5 3.5 (Find the wrong no. in this series)
1. 4
2. 5
3. 11
4. 19
Sol: Option 1
Explanation: 35-19 = 16, 19-11 = 8, 11-7 = 4, 7-5 = 2, 5-4 = 1, 4-3.5 = .5 The difference is halved every time. Thus the wrong number is 4.5, it should be 4.
22. 5, 16, 49, 104, ?
A. 171
B. 191
C. 181
D. 161
Answer: C
Explanation: 5+11 =16, 16+33 =49, 49+55 =104, 104+77 =181.
23. 7, 26, 63, 124, 215, 342, ?
A. 481
B. 511
C. 391
B. 421
Answer: B
Explanation: Numbers are (2^3 – 1), (3^3 – 1), (4^3 – 1), (5^3 – 1), (6^3 – 1), (7^3 – 1) etc.
So, the next number is (8^3 – 1) = (512 – 1) = 511.
24. 3, 12, 27, 48, 75, 108, ?
A. 147
B. 183
C. 162
D. 192
ans. A
Explanation: The numbers are 3 x 1^2, 3 X 2^2, 3 X 3^2, 3 X 4^2, 3 X 5^2, 3 X 6^2, Missing number= 3 X 7^2 = 147
25. 1, 6, 13, 22, 33, ?
A. 44
B. 45
C. 46
D. 47
ans. c
The pattern is + 5, + 7, + 9, + 11,...
.'. Missing number = 33 + 13 = 46.
26. 3, 6, 18, 72, ?
A. 144
B. 360
C. 288
D. 216
ans. B
Explanation: pattern is * 2, * 3,*4, number is = 72 x 5 = 360.
27. 3, 7, 6, 5, 9, 3, 12, 1, 15, ?
A. 18
B. 13
C. -1
D. 3
ans. c
Explanation: There are two series, beginning respectively with 3 and 7. In one 3 is added and in another 2 is subtracted. The next number is 1 – 2 = -1.
28. 2, 4, 12, 48, 240,?
A. 960
B. 1440
C. 1080
D. 1920
ans. B
Explanation: Go on multiplying the given numbers by 2, 3, 4, 5, 6.
So, the correct next number is 1440.
29. 3, 5, 5, 19, 7, 41, 9, ?
A) 71
B) 61
C) 79
D) 69
Answer: A) 71
Explanation: First series : 3, 5, 7, 9. Second series : 5, 19, 41, ?
Difference of Second series are 14, 22, 30 etc. Next term is 41+30 i.e equal to 71.
30. 132 156 ? 210 240 272
A) 196
B) 182
C) 199
D) 204
Answer: B) 182
Explanation: The given series follows a logic that 11 x 12, 12 x 13, 13 x 14, 14 x 15, 15 x 16,…. So the missing number is 13 x 14 = 182.
31. 1, 2, 6, 15, 31, 56, 91
A) 31
B) 15
C) 56
D) 91
Answer: D) 91
Explanation: The difference of the two consecutive numbers are 1, 4, 9, 16, 25, 35.
This is clearly , +(12), +(22), +(32), +(42), +(52),+(62) . Here 35 is wrong, So our wrong number is 91
32. 1, 2, 3, 10, ?, 9802
A) 99
B) 199
C) 299
D) 999
Answer: Option A
Explanation: 2 = 1^2 + 1, 3 = 2^2 − 1, 10 = 3^2 + 1. Now 10^2 − 1 = 99, 9802 = 99^2 + 1.
33. Find out the wrong term in the series 2, 3, 4, 4, 6, 8, 9, 12, 16
A) 9
B) 12
C) 16
D) 8
Answer: A) 9
Explanation: The given sequence is a combination of three series:
i)1st, 4th, 7th terms i.e, 2, 4, 9
ii)2nd, 5th, 8th terms i.e, 3, 6, 12
iii)3rd, 6th, 9th terms i.e, 4, 8, 16
In each one of i, ii, iii, each term is twice the preceding term.
So, 9 is wrong and must be replaced by (4*2) = 8
34. 8, 15, 28, 53, ?, 199
A) 101
B) 102
C) 103
D) 104
Answer: Option B
Explanation: Here the series of the form is x2 − 1, x2 − 2, x2 − 3,...
53 x 2 - 4 = 106 - 4 = 102
35. 0, 7, 26, 63, 124, ?
A) 125
B) 215
C) 512
D) 251
Answer: B
36. 7, 8, 18, 57, ?, 1165, 6996
A) 228
B) 542
C) 232
D) 415
Answer: Option C
Explanation: Here 2nd number = (1st number x 1 )+1
3rd number = (2nd number x 2 )+2
4th number = (3rd number x 3 )+3 and so on..
Therefore, 5th number = (4th number x 4) +4 =57 x 4 + 4 =232.
37. 8, 27, 125, 343, 1381 (Find the wrong number in the given series.)
A) 27
B) 8
C) 343
D) 1381
Answer: D) 1381
Explanation: Given series follows Cubes on Prime Numbers i.e 23, 33, 53,...but 93 is 1331. so, 1381 is wrong.
38. Find the wrong number in the given series.
8, 27, 125, 343, 1381
A) 27
B) 8
C) 343
D) 1381
Answer: D) 1381
Explanation: Given series follows Cubes on Prime Numbers i.e 23, 33, 53,...but 93 is 1331. so 1381 is wrong
39. Find out the wrong term in the series 0, 2, 3, 5, 8, 10, 15, 18, 24, 26, 35
A) 18
B) 35
C) 24
D) 8
Answer: A) 18
Explanation: The given sequence is a combination of two series:
i)0, 3, 8, 15, 24, 35
ii)2, 5, 10, 18, 26
The pattern in both i, ii is +3, +5, +7, . . . .
So, in ii) 18 is wrong and must be replaced by (10 + 7) = 17
40. Choose the correct alternative that will continue the same pattern and replace 'x' in series 4,9,25,x,121,169,289,361
A) 81
B) 36
C) 64
D) 49
Answer: D) 49
Explanation: The given series consists of squares of consecutive prime numbers
2*2, 3*3, 5*5, . . . . , 11*11, 13*13, 17*17
41. Find the next number in the given sequence?
11, 17, 39, 85, ?
A) 133
B) 143
C) 153
D) 163
Answer: D) 163
Explanation: Her the given number series is 11, 17, 39, 85, ?
1111 + (32 − 3) = 1717 + (52 − 3) = 3939 + (72 − 3) = 8585 + (92 − 3) = 163
Hence, the next number in the given sequence is 163.
42. Find out the wrong term in the series 3, 7, 15, 39, 63, 127, 255, 511
A) 39
B) 255
C) 127
D) 63
Answer: A) 39
Explanation: The correct pattern is *2+1
So, 39 is wrong and must be replaced by (15 * 2 + 1) = 31
Which Number would come in place of the underline mark in the series.
43. 3, 9, 21, ___ , 93
A) 39
B) 45
C) 48
D) 51
Answer: B) 45
Explanation: First difference is 6 and second is 12. But if we take third as 18, then fourth difference will be 24. Then 93 can not be the last term. So we have to take the difference as 6, 12, 24 and 48.
So Answer is 21+24 = 45
44. 3,14,58,234,938,?
1 : 4152
2 : 4110
3 : 3754
4 : 4154
Answer- 3 (3754)
Explanation- x4+2
45. 3,25,255,2545,25455, ?
1 : 254550
2 : 254555
3 : 254545
4 : 254555
Answer-3 (254545)
Explanation- 25=(3×10)-5
255=(25×10)+5
2545=(255×10)-5
25455=(2545×10)+5
?=(2545×10)-5 = 254545
46. 4725,1050,300,120,80,?
1 : 40
2 : 160
3 : 120
4 : 110
Answer-2 (160)
Explanation- 4725 / 4.5=1050
1050/3.5=300
300/2.5=120
120/1.5=80
80/0.5=160
47. 76 , 43 , 13 ,………
1.3
2.4
3.11
4.6
Answer – 2 . 4
Explanation – (7×6)+1=43 ; (1×3)+1=4
48. 6, 7, 16, 51, …………..
1.258
2.254
3.208
4.234
Answer – 3. 208
Explanation – (6×1)+1=7; (7×2)+2=16; (16*3)+3=51; (51×4)+4=208
49. 2 , 30 , 130 , 350 , ………….
1.738
2.783
3.638
4.530
Answer – 1. 738
Explanation – ( 1^3)+1=2; (3^3)+3=30 (5^3)+5=130 (7^3)+7=350 (9^3)+9=738
50. 3 , 10 , 20 , 27 , 54 , 61,…….
1.68
2.122
3.105
4.72
Answer – 2. 122
Explanation – 3+7=10; 10+10=20 20+7=27 27+27=54 54+7=61; 61+61=122
Comments
Post a Comment