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

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 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 is +5, +7, +9, +11
So next number will be +13
=> 33+13 = 46

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:

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