Which of the following numbers will replace the question mark (?) in the given series?

8, 18, 38, 78, 158,?

Correct option is A

Given: 8, 18, 38, 78, 158,?
Observe how the numbers are increasing:
18 - 8 = 10, 38 - 18 = 20, 78 - 38 = 40 and 158 - 78 = 80
Logic: The difference between consecutive terms is doubling each time:
10 × 2 = 20
20 × 2 = 40
40 × 2 = 80
Following this pattern, the next difference should be:
80 × 2 = 160
So, the next number in the series would be:
158 + 160 = 318
Thus, the number that replaces the question mark is 318.