Number Series Practice Questions for SBI PO

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Mentor for Bank Exams
Number Series Practice Questions for SBI PO
Directions (1 – 5): What will come in place of question mark (?) in the following number series?
1. 281 218 163 116 ?
a) 77
b) 78
c) 56
d) 52
e) 85
2. 900 810 440 392 180 ?
a) 48
b) 150
c) 90
d) 45
e) 78
3. 57 73 91 111 ? 157.
a) 143
b) 133
c) 123
d) 135
e) None of these
4. 57 85 105 117 ?
a) 121
b) 108
c) 138
d) 136
e) 135
5. 39 48 53 54 51 ?
a) 59
b) 44
c) 33
d) 46
e) 48
Directions (6 – 10): In each of these questions a number series is given. In each series only one number is wrong. Find the wrong number.
6. 3 16 19 46 55 92 105
a) 3
b) 19
c) 46
d) 92
e) 105
7. 3 12 30 60 108 168 252
a) 12
b) 30
c) 108
d) 168
e) 252
8.1/3 1/2 3/5 2/3 6/7 6/8 8/9
a) 1/3
b) 1/2
c) 3/5
d) 2/3
e) 6/7
9. 10 21 36 56 78 105 136
a) 10
b) 56
c) 78
d) 105
e) 136
10. 100 80 64 51.2 40.5 32.768 26.2144 20.97152
a) 40.5
b) 64
c) 32.768
d) 26.2144
e) 20.97152
Solutions:
1. The series is 172 – 8 , 152 – 7 , 132 – 6, 112 – 5 , 92 – 4 , 72 – 3 , ……..
Answer is : a)
2. The series is 103 - 102 = 900, 93 + 92 = 810, 83 – 82 = 448 , 73 + 72 = 392, 63 – 62 = 180, 53 + 52= 150
, ………..
Answer is: b)
3. The series is 72 + 8 = 57, 82 + 9 =73, 92 +10 = 91, 102 + 11= 111, 112 + 12 = 133, 122 + 13= 157,
132 + 14 = 183,..
Answer is: b)
4. The series is 6 × 9.5 = 57, 10 × 8.5 = 85, 14 × 7.5 = 105, 18 × 6.5 =117, 22 × 5.5 = 121, 26 × .5 =
117,….
Answer is: a)
5. The series is 6 × 9 – 15 = 39, 8 × 8 – 16 = 48, 10 × 7 – 17 = 53, 12 × 6 – 18 = 54, 14 × 5 – 19 = 51,
16 × 4 – 20 = 44, 18 × 3 -21 = 33,…….
Answer is: b)
6. The series is 12 + 22 – 2, 22 + 32 + 3, 32 + 42 – 4, 42 + 52 + 5, 52 + 62 – 6, 62 + 72 + 7, 72 + 82 - 8….
Hence there should be 21 in place of 19.
Answer is: b
7. The series is (1×2×3)/2, (2×3×4)/2, (3×4×5)/2, (4×5×6)/2, (5×6×7)/2, (6×7×8)/2, (7×8×9)/2
= 3, 12, 30, 60, 105, 168, 252
Hence there should be 105 in place on 108.
Answer is: c)
8. The series is (12 + 1) / (22 +2) , (22 + 2) / (32 + 3) , (32 + 3)/ (42 + 4) , (42 + 4) / (52 + 5) , (52 + 5) /
(62 + 6), (62 +6) / (72 +7), (72 +7) / (82 +8)
= 2/6, 6/12, 12/20, 20/30, 30/42, 42/56, 56/72
= 1/3 , 1/2, 3/5, 2/3, 5/7, 6/8, 8/9
Hence there should be 5/7 in place of 6/7.
Answer is: e)
9. The series is 2 × 3 + 22, 3 × 4 + 32, 4 × 5+ 42, 5 × 6 +52, 6 × 7 +62, 7 × 8 + 72, 8 × 9 + 82,…..
= 10, 21, 36, 55, 78, 105, 136
Hence there should be 55 in place of 56.
Answer is: b)
10. The series is 100 × (80/100) = 80, 80 × (80/100) = 64, 64 × 80/100 = 51.2, 51.2 × 80/100 = 40.96, 40.96 ×80/100 = 32.768, 32.768 × 80/100 = 26.2144, 26.2144 × 80/100 = 20.97152
Hence there should be 40.96 in place of 40.5
Answer is: a)