NUMBER SERIES
What should come in place of the question marks (?) in the following number
series ?
Q.1. 354 , 180 , 64 , 21 , 10.2 , (?)
A. 5.6
B. 8.7
C. 3.8
D.1.7
E. none of these
Q.2. 4.5 , 18 , 2.25, (?) , 1.6875,
A. 27
B. 25.5
C. 36
D.40
33.75
E. none of these
Q.3. 59.76, 58.66, 56.46, 52.06, (?), 25.66
A.48.08
B.46.53
C. 43.46
D.43.26
E. none of these
Q.4. 12, 15, 21, 24, 30, 33, 39, (?)
A.47
B.56
C. 49
D.45
E. none of these
Q.5. 1, 4, 18, 84, 440, (?)
A. 2760
B. 2640
C. 2840
D.2670
E. none of these
Q.6. 58, 82, 102, 128, 166, (?)
A. 198
B. 204
Q.7. 8.94, 8.37,
A. 5.56
C. 208
7.75,
B. 5.48
E. 220
7.07, 6.32, (?)
C. 5.29
Q.8. 48123, 51876, 31490,
A. 42326
D.216
B. 83149
D.5.12
E. none of these
68509, 57673,
C. 23021
D.64357
(?)
E. none of these
Q.9. 1, 1, 8, 34, 97, (?)
A.112
B. 162
C. 205
D.181
E. none of these
Q.10. 1605, 1508, 1419, 1336, 1257, (?)
A.1180
B. 1184
C. 1190
D.1188
E. none of these
SOLUTION
(1).b
:(2). A 4.5 × 4 = 18
= 2.25
2.25 × 12 = 27
= 1.6875
1.6875 × 20 = 33.75
+ 3 = 180
+ 4 = 64
+ 5 = 21
+ 6 = 10.2
+ 7 = 8.7
(3).d
(4).c 12 + ( 1+2) =15
15 + ( 1+5) =21
21 + ( 1+2) =24
24 + ( 2+4) =30
30 + ( 3+0) =33
33 + ( 3+3) =39
39 + ( 3+9) =51
+ 3 = 180
+ 4 = 64
+ 5 = 21
+ 6 = 10.2
+ 7 = 8.7
(5).d (1 + 1) × 2 = 4
(4 + 2) × 3 = 18
(18 +3) × 4 = 84
(84 + 4) × 5 = 440
So the next term will be
(440 + 5) × 6 = 2670
(6).a 19 × 2 + 1 = 58
20 × 4 + 2 = 82
21 × 5 ÷ 3 = 102
22 × 6 - 4 = 128
23 × 7 + 5 = 166
24 × 8 + 6 = 198
(7).b √ = 8.94
√ = 8.37
√ = 7.75
√ = 7.07
√ = 6.32
Hence the next term would be √
5.48
(8).a 99999 – 48123 = 51876
99999 – 31490 = 68509
99999 – 57673 = 42326
(9).e 1 + (
=1
1+(
=8
8+(
= 34
34 + (
= 97
So, the next term is
97 + (
= 221
=
(10).b The difference between the terms are
97, 89, 83, 79, 73, i.e. Consecutive
decreasing prime numbers. Hence the next
term is
1257 -73 = 1184