120, 99, 80, 63, 48, ?

Answer: Option A

Explanation:

The pattern is - 21, - 19, - 17, - 15,.....

So, missing term = 48 - 13 = 35.

589654237, 89654237, 8965423, 965423, ?

Answer: Option D

The digits are removed one by one from the beginning and the end in order alternately

so as to obtain the subsequent terms of the series.

3, 10, 101,?

Answer: Option C

Each term in the series is obtained by adding 1 to the square of the preceding term.

So, missing term = (101)^{2} + 1 = 10202.

In the series 2, 6, 18, 54, ...... what will be the 8th term ?

Answer: Option B

Clearly, 2 x 3 = 6, 6 x 3 = 18, 18 x 3 = 54,.....

So, the series is a G.P. in which a = 2, r = 3.

Therefore 8th term = ar^{8-1} = ar^{7} = 2 x 3^{7} = (2 x 2187) = 4374.

125,80,45,20,?

The pattern is - 45, - 35, - 25, .....

So, missing term = 20 - 15 = 5.