Question Detail

Complete the series
20, 19, 17, ...., 10, 5

Answer: Option D

Explanation:

Pattern is, -1, -2, ..,.. , -5

So -3 and -4 will fill the blanks to make it a pattern.

Next number will be 17-3 = 14

1. Complete the series 95, 115.5, 138, ..., 189

160.5
162.5
164.5
166.5

Answer: Option B

Explanation:

Pattern in the series is, +20.5 , +22.5,
Next will be +24.5
138 + 24.5 = 162.5

2. 6, 11, 21, 36, 56, ... ?

Answer: Option A

Explanation:

Pattern is +5, +10, +15, + 20. So next will be 56+25 = 81

3. What number should come next in the series, 1, 2, 3, 5, 8, ?

Answer: Option D

Explanation:

In this series, each term is the sum of preceding two terms as,
1+2 = 3
3+2 = 5
5+3 = 8
Next term in the series will be,
8+5 = 13

4. 8, 9, 8, 7, 10, 9, 6, 11, 10, (...), 12

Answer: Option C

Explanation:

Please note that above sequence is containing 3 series
Series 1 : 8, 7, 6, (..)
Series 2 : 9, 10, 11, 12
Series 3 : 8, 9, 10

In series 1 pattern is -1. So missing term will be 6-1 = 5

5. In the series 2, 6, 18, 54, ... what will be the 8th term ?

4174
4150
4274
4374

Answer: Option D

Explanation:

We can see the given series is in G.P.
as 2*3 = 6, 6*3 = 18, 18*3 = 54
So a = 2 , r = 3
nth term in G.P. is
\begin{aligned}
ar^{n-1} \\
= 2*3{8-1} \\
= 2*3^7 \\
= 2*2187 = 4374
\end{aligned}