Question Detail

1, 2, 5, 12, 27, 58, 121, ?

Answer: Option A

Explanation:

Pattern in the series is *2+1, *2+2, *2+3,.....

Term which replaces the question mark in the series is
121 * 2 + 6 = 248

1. 6, 11, 21, 36, 56, ... ?

Answer: Option A

Explanation:

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

2. 3, 12, 27, 48, 75, 108,

Answer: Option D

Explanation:

Series is having pattern
\begin{aligned}
3*1^2, 3*2^2, 3*3^2, ......\\
\text{Next will be } 3*7^2 = 147
\end{aligned}

3. In the series 3, 9, 15.. what will be the 21st term ?

Answer: Option A

Explanation:

We can judge that it is A.P.
With 6 as difference
nth term in A.P. = a+(n-1)d
a= 3, n = 21, d = 6
So, 21st term will be = 3+(20)6 = 123

4. 5, 6, 7, 8, 10, 11, 14, (...) ?

Answer: Option D

Explanation:

Please check that given sequence consists of two series

Series 1: 5, 7, 10, 14
Series 2: 6, 8, 11, ...

In series 2 pattern is +2, +3, Next will be +4
So required number in the series will be 11+4 = 15

5. 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