36, 34, 30, 28, 24, ... What number should come next?

Answer: Option D

Explanation:

Given sequence is combination of two series
Series 1 : 1,3,6,10,..
Series 2 : 1,9,36,100,225

In series 1 pattern is +2, +3, +4. So next term will be
10+5 = 15

Answer: Option C

Explanation:

\begin{aligned}
\text{Pattern is }\\
+1^2-1, +2^2-1, +3^2-1,+4^2-1 \\
5^2-1 = 28 + 24 \\
= 52
\end{aligned}

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

Answer: Option B

Explanation:

Pattern in the series is, +5, +9, .., .., +21, +25
So 4 is getting increased at every term addition.
Missing term in the series will be 15+(9+4)
= 15+13 = 28

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