8, 10, 14, 18, (...), 34, 50, 66

Answer: Option A

Explanation:

Please look carefully at the series, its pattern is,
-1, +2, -1, +2, -1, so next will be +2
23+2 = 25

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

Answer: Option A

Explanation:

Pattern in the series is, -2, -4, -2, -4. So next term will be -2
24 -2 = 22

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 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