Which number should be replaced with x in following series :

2, 3, 5, 7, 11, x, 17

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+1, *2+2, *2+3,.....

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

Answer: Option C

Explanation:

Pattern in the series is +4, +8, +12, +16.
Next term will be 45 + 20 = 65

Answer: Option B

Explanation:

Pattern is, +4, +8, +16, +32, so next will be +64
81+64 = 145

Answer: Option C

Explanation:

Pattern for the given series is, +8, +8, +16, +16, +24

So next will be +24, 73+24 = 97