Directions (1-5): What will come in the place of question (?) mark in the following number series:
Q1. 12, 7, 8.5, 14.75, ?, 83
(a) 30
(b) 24
(c) 32
(d) 36
(e) 48
Q2. 12, 78, 395, 1584, 4755, ?
(a) 9512
(b) 9516
(c) 9518
(d) 9520
(e) 9580
Q3. 26, 53, 214, 1287, 10300, ?
(a) 95000
(b) 100005
(c) 103000
(d) 101005
(e) 103005
Q4. 4187, 2857, 2129, 1787, 1663, ?
(a) 1647
(b) 1642
(c) 1627
(d) 1637
(e) 1630
Q5. 27, 27, 54, 18, 72, ?
(a) 19.6
(b) 16.8
(c) 18.8
(d) 12.8
Solutions
S1. Ans.(c)
Sol.
Pattern of series
12 × 0.5 + 1 = 7
7 × 1 + 1.5 = 8.5
8.5 × 1.5 + 2 = 14.75
? = 14.75 × 2 + 2.5 = 32
32 × 2.5 + 3 = 83
S2. Ans.(a)
Sol.
Pattern of series —
12 × 6 + 6 = 78
78 × 5 + 5 = 395
395 × 4 + 4 = 1584
1584 × 3 + 3 = 4755
? = 4755 × 2 + 2 = 9512
S3. Ans.(e)
Sol.
26 × 2 + 1 = 53
53 × 4 + 2 = 214
214 × 6 + 3 = 1287
1287 × 8 + 4 = 10300
? = 10300 × 10 + 5 = 103005
S4. Ans.(d)
Sol.
S5. Ans.(e)
Sol.
Pattern of series
27 ÷ 1 = 27
27 × 2 = 54
54 ÷ 3 = 18
18 × 4 = 72
? = 72 ÷ 5 = 14.4
. .