Question

Which of the following numbers will replace the question mark (?) in the given series? 8, 18, 38, 78, 158,?

• A. 306
• B. 324
• C. 224
• D. 318

Answer 1

Answer:

D. 318

Let's analyze the pattern in the series:

8, 18, 38, 78, 158, ?

Now check the differences between consecutive terms:

• 18 – 8 = 10

• 38 – 18 = 20

• 78 – 38 = 40

• 158 – 78 = 80

The pattern in differences is:
+10, +20, +40, +80

This appears to be doubling each time.

So the next difference should be:
+160

Now add 160 to the last term:

158 + 160 = 318