Question

Which of the following numbers will replace the question mark (?) in the given series? 16, 18, 27, 55, 120,?

• A. 246
• B. 230
• C. 510
• D. 240

Answer 1

Answer:

A. 246

The number that will replace the question mark (?) in the series is 246.

The series grows by adding the cube of consecutive numbers plus 1 ($n^3 + 1$) to each preceding term:

• 16 $+ (1^3 + 1) = 16 + 2 = \mathbf{18}$

• 18 $+ (2^3 + 1) = 18 + 9 = \mathbf{27}$

• 27 $+ (3^3 + 1) = 27 + 28 = \mathbf{55}$

• 55 $+ (4^3 + 1) = 55 + 65 = \mathbf{120}$

• 120 $+ (5^3 + 1) = 120 + 126 = \mathbf{246}$