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

Answer: Option C

Explanation:

In this series the pattern is +4, +8, +12, +16, so next will be +20

Term which will replace the question mark in this series will be 45+20 = 65

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

Answer: Option B

Explanation:

There are two series in this sequence
Series 1: 13, 24, 35, 46, 57
Series 2: 32, 43, (..), 65, 76

The pattern it is following is +11
Missing number will be 43 + 11 = 54

Answer: Option A

Explanation:

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

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