Find the wrong number in the series:
िनदश: ृंखला म गलत सं ा ात कीिजये:
Q1. 3 7 16 35 72 153 312
a) 7
b) 153
c) 35
d) 72
e) 16
Q2. 18 20 23 32 48 73 109
a) 20
d) 48
Q3. 7
4
b) 23
e) 73
5
9
c) 32
20 51 160.5
a) 4
b) 5
c) 9
d) 20
e) 51
Q4. 6 10 14 34 66 130 258
a) 10
b) 14
c) 34
d) 66
e) 130
Q5. 2 7 30 138 524 1557 3102
a) 7
b) 30
c) 138
d) 524
e) 1557
Q6. 46, 52, 60, 70, 82, 95
a) 46
b) 52
c) 60
d) 70
e) 95
Q7. 2, 8, 25, 90, 372, 1870, 11226
a) 25
b) 372
c) 11226
d) 90
e) 2
Q8. 7, 8, 18, 56, 232, 1165, 6996
a) 232
b) 1165
c) 56
d) 18
e) 7
Q9. 1, 13, 36, 85, 181, 373, 757
a) 36
b) 373
c) 757
d) 85
e) 1
Q10. 9216, 2304, 576, 144, 36, 12
a) 576
b) 12
c) 9216
d) 144
e) 2304
Q11. 10.8, 9.9, 11.9, 9, 12.6, 8.1
a)10.8
b) 9.9
c) 9
d)11.9
e)12.6
Q12. 8, 10, 20, 50, 120, 248
a) 120
b) 8
c) 20
d) 248
e) 10
Q13. 9, 5, 6, 11, 23, 60
a) 9
b) 6
c) 11
d) 23
e) 60
Q14. 11, 20, 32, 60, 116, 228
a) 11
b) 60
c) 32
d) 116
e) 20
Q15. 360, 354, 347, 322, 273, 152
a) 152
b) 322
c) 347
d) 354
e) 360
Q16. 3.7, 8.7, 23.7, 48.7, 84.7, 128.7
(a) 23.7
(b) 48.7
(c) 84.7
(d) 128.7
(e) 8.7
Q17. 1, 14, 31, 64, 133, 264
(a) 14
(b) 31
(c) 264
(d) 133
(e) 64
Q18. 2, 1, 1, 2, 8, 32, 1024
(a) 32
(b) 2
(c) 8
(d) 1
(e) 1024
Q19. 168, 288, 360, 528, 841, 960
(a) 168
(b) 841
(c) 288
(d) 360
(e) 528
Q20. 7.2, 72, 9, 54, 13.5, 28
(a) 72
(b) 9
(c) 28
(d) 13.5
(e) 54
Q21. 11, 20, 32, 60, 116, 228
a) 11
b) 60
c) 32
d) 116
e) 20
Q22. 360, 354, 347, 322, 273, 152
a) 152
b) 322
c) 347
d) 354
e) 360
Q23. 71 70 78 69 133 208 324
a) 69
b) 133
c) 208
d) 70
e) 324
Q24. -3 -1 10 39 89 167
a) -1
b) 39
c) 89
d) 10
e) 167
Q25. 1 2 6 12 20 30
a) 6
b) 20
c) 12
d) 30
e) 1
Q26. 32, 39, 65, 128, 253, 467, 809, 1320
a) 39
b) 65
c) 253
d) 467
e) 32
Q27. 38, 49, 62, 72, 77, 91, 101
a) 49
b) 72
c) 77
d) 91
e) 38
Q28. 19, 22, 32, 46, 73, 108, 158
a) 22
b) 46
c)73
d) 19
e) 158
Q29. 47, 44, 45, 46, 33, 57, 3, 88
a) 44
b) 57
c) 46
d) 3
e) 47
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Q30. 45, 131, 228, 338, 466, 619, 800
a) 131
b) 466
c) 619
d) 45
e) 800
Q31. 2, 11, 38, 197, 1172, 8227 65806
a) 11
b) 38
c) 197
d) 1172
e) 8227
Q32. 16, 19, 21, 30, 46, 71, 107
a) 19
b) 21
c) 30
d) 46
e) 71
Q33. 7, 9, 16, 25, 41, 68, 107, 173
a) 107
b) 16
c) 41
d) 68
e) 25
Q34. 2, 3, 6, 18, 109, 1944, 209952
a) 3
b) 6
c) 18
d) 109
e) 1944
Q35. 1, 3, 6, 11, 20, 39, 70
a) 3
b) 39
c) 11
d) 20
e) 6
Q36. 46, 52, 60, 70, 82, 95
a) 46
b) 52
c) 60
d) 70
e) 95
Q37. 2, 8, 25, 90, 372, 1870, 11226
a) 25
b) 372
c) 11226
d) 90
e) None of these
Q38. 7, 8, 18, 56, 232, 1165, 6996
a) 232
b) 1165
c) 56
d) 18
e) None of these
Q39. 1, 13, 36, 85, 181, 373, 757
a) 36
b) 373
c) 757
d) 85
e) 181
Q40. 9216, 2304, 576, 144, 36, 12
a) 576
b) 12
c) 9216
d) 144
e) 36
Q41. 602, 598, 591, 563, 498, 372, 155
a) 155
b) 591
c) 498
d) 598
e) 120
Q42. 130, 60. 34, 18, 10, 6, 4
a) 60
b) 18
c) 6
d) 10
e) 4
Q43. 1, 8, 66, 460, 2758, 13785, 55146
a) 460
b) 2758
c) 66
d) 8
e) 55146
Q44. 56, 57, 48, 73, 24, 105, -10
a) 57
b) 73
c) 105
d) -10
e) 24
Q45. 2, 2, 13, 59, 363, 2519, 20161
a) 13
b) 20161
c) 2519
d) 59
e) 363
Q46. 3, 1, 3, 7, 3, 0.6, 3, 0.5, 3
a) 1
b) 7
c) 0.5
d) 3
e) 0.6
Q47. 2, 6, 13, 26, 54, 100, 197
a) 26
b) 100
c) 54
d) 197
e) 13
Q48. 10.8, 9.9, 11.9, 9, 12.6, 8.1
a) 10.8
b) 9.9
c) 9
d) 11.9
e) 12.6
Q49. 8, 10, 20, 50, 120, 248
a) 120
b) 8
c) 20
d) 248
e) 10
Q50. 9, 5, 6, 11, 23, 60
a) 9
b) 6
c) 11
d) 23
e) 60
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Solution
1. Sol.
The series is / ृं खला है ×2+ 1; ×2+2, ×2+3, ×2+4, ×2+5
∴ 35 × 2 + 4 = 74 𝑛𝑜𝑡 72
2. Sol.
The series is / ृं खला है 18 + 1² = 19 not 20
19 + 2² = 23
23 + 3² = 32
32 + 4² = 48
48 + 5² = 73
73 + 6² = 109
3. Sol.
The series is / ृंखला है×0.5 + 0.5, ×1 + 1, ×1.5 + 1.5, ×2 + 2, ×2.5 +
2.5, ×3 + 3
∴ 20 × 2.5 + 2.5 = 52.5 𝑛𝑜𝑡 51
4. Sol .
The series is / ृं खला है ×2 – 2, ×2 – 2, ×2 – 2, ×2 – 2
∴ 10 × 2 − 2 = 18 𝑛𝑜𝑡 14
5. Sol.
(2 – 1) × 7 = 7
(7 – 2) × 6 = 30
(30 – 3) × 5 = 135 not 138
(135 – 4) × 4 = 524
(524 – 5) × 3 = 1557
(1557 – 6) × 2 = 3102
6. Sol.
46+ 6= 52
52+ 8= 60
60+10 = 70
70+ 12 = 82
82+ 14 = 96 then 95 is wrong) 82+ 14 = 96
7.Sol:
(2+6) ×1=8
(8+5) ×2=26 then 25 is wrong. )
(8+5)×2=26 तो 25 गलत है (
(26+4) ×3=90
(90+3) ×4=372
(372+2) ×5=1870
(1870+1) ×6=11226
8. Sol.
7×1+1=8
8×2+2=18
18×3+3=57
57×4+4=232
232× 5+5=1165
1165× 6+6=6996
Wrong number is 56
9. Sol.
1+12=13
13+24=37
37+48=85
85+96=181
181+192=373
373+384=757
Wrong number is 36 (गलत सं
10. Sol.
9216/4=2304
2304/4=576
576/4=144
144/4=36
36/4=9
Wrong number is 12
(गलत सं ा 12 है )
11. Sol.
ा 36 है )
12. Sol.
13. Sol.
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14. Sol.
15. Sol.
16. Ans.(c)
Series is +5, +15, +25, +35, +45
∴ wrong term = 84.7
17. Ans.(c)
18. Ans.(a)
Series is ×0.5, ×1, ×2, ×4, ×8, ×16
∴ Required term = 8 × 8
= 64 ≠ 32
19. Ans.(b)
Series is 13² - 1, 17² - 1, 19² - 1, 23²- 1, 31² - 1
∴ wrong term = 841
20. Ans.(c)
Series is ×10, ÷ 8, ×6, ÷ 4, ×2
∴ Wrong term = 28
21. Sol e)
22. Sol d)
2 − 3 = −1
3 − 4 = 11
4 − 5 = 39
5 − 6 = 89
6 − 7 = 167
Hence, wrong number is 10
25. Sol e)
1 −1=0
2 −2=2
3 −3=6
4 − 4 = 12
5 − 5 = 20
6 − 6 = 30
Hence, wrong number is 1
26. Sol.
27. Sol.
38 = 3+8 = 11 = 38 +11 = 49
49 = 4+9 = 13 = 49 +13 = 62
62 = 6+2 = 8 = 62 + 8 = 70 ≠ 72
70 = 7+0 = 7 = 70+ 7 = 77
77 = 7+7 = 14 = 77+14 = 91
91 = 9+1 = 10 = 91+10 = 101
Hence, 72 is the wrong number.
28. Sol.
Hence, wrong number is 591
23. Sol ( c)
71 − 1 = 70
70 + 2 = 78
78 − 3 = 69
69 + 4 = 133
133 − 5 = 108
108 + 6 = 324
Hence, wrong number is 208
24. Sol d)
1 −2 =3
29. Sol.
First series 47, 45, 33, 3
47-(1×2) = 45
45-(3×4) = 33
33- (5×6) = 3
Second series 44, 46, 57, 88
44 + (1×2) = 46
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46 + (3×4) = 58 ≠ 57
58 + (5×6) = 88
30. Sol.
31. Sol.
11 = 2 × 3 + 5
38 = 11 × 4 – 6
197 = 38 × 5 + 7
1172 ≠ 197 × 6 – 8
1172 is wrong and it should be replaced by 197
× 6 – 8 = 1174
32. Sol.
107 – 71 = 36 = 6 2
71 – 46 = 25 = 52
46 – 30 = 16 = 42
30 – 21 = 9 = 32
21 – 19 = 2 ≠ 22
19 should be replaced by 17 for which 21 – 17
= 22
33. Sol.
16 = 9 + 7
25 = 16 + 9
41 = 25 + 16
66=68 ≠ 41 + 25
34. Sol.
2×3=6; 3×6=18; 6×18=108;
18×108=1944….
35. Sol.
1×2+1=3;
3×2+0=6;
6×2-1=11;
11×2-2=20;
20×2-3=37….
36. Sol.
46+ 6= 52
52+ 8= 60
60+10 = 70
70+ 12 = 82
82+ 14 = 96 then 95 is wrong.
37. Sol.
(2+6)×1=8
(8+5)×2=26 then 25 is wrong.
(26+4)×3=90
(90+3)×4=372
(372+2)×5=1870
(1870+1)×6=11226
38. Sol.
7×1+1=8
8×2+2=18
18×3+3=57
57×4+4=232
232× 5+5=1165
1165× 6+6=6996
Wrong number is 56
39. Sol.
1+12=13
13+24=37
37+48=85
85+96=181
181+192=373
373+384=757
Wrong number is 37
40. Sol.
9216/4=2304
2304/4=576
576/4=144
144/4=36
36/4=9
Wrong number is 12
41. Sol d)
Series following the pattern,
-13+1, -23+1, -33+1, -43+1, -53+1, -63+1 So
600 will come instead of 598.
42. Sol a)
Series following the pattern,
÷0.5+1, ÷0.5+1, ÷0.5+1, ÷0.5+1, ÷0.5+1,
÷0.5+1, ÷0.5+1
So 66 will come instead of 60.
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43. Sol a)
Here
1×9–1=8
8 × 8 + 2 = 66
66 × 7 – 3 = 459
459 × 6 + 4 = 2758
2758 × 5 – 5 = 13785
13785 × 4 + 6 = 55146
44. Sol d)
56 +12= 57
57 – 32 = 48
48+ 52 = 73
73- 72 = 24
24 + 92 = 105
105 -112 = -16
45. Sol. e)
2×3–4=2
2 × 4 + 5 = 13
13 × 5 – 6 = 59
59 × 6 + 7 = 361
361 × 7 – 8 = 2519
2519 × 8 + 9 = 20161
46. Sol d)
3 × 1/3 = 1
1×3=3
3 × 1/4 = 0.75
0.75 × 4 = 3
3 × 1/5 = 0.6
0.6 × 5 = 3
3 × 1/6 = 0.5
0.5 × 6 = 3
47. Sol c)
2×2+2=6
6 × 2 + 1 = 13
13 × 2 + 0 = 26
26 × 2 – 1 = 51
51 × 2 – 2 = 100
100 × 2 – 3 = 197
48. Sol d)
49. Sol a)
50. Sol c)
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For any queries or suggestions email us @ mathsbyarunsir003@gmail.com or whatsapp @ 8881331466