Select the missing term from the following number series ?

Question

7, 4, 5, 9, ?, 52.5, 160.5

[A] 16

[B] 18

[C] 20

[D] 22

Answer & Explanation
Option: [C]

The missing term is 20

7 x 0.5 + 0.5 = 4

4 x 1 + 1 = 5

5 x 1.5 + 1.5 = 9

9 x 2 + 2 = 20

20 x 2.5 + 2.5 = 52.5

52.5 x 3 + 3 = 160.5