Question

What should come in place of the question mark (?) in the given series? 650 660 669 677 684 ?

• A. 686
• B. 688
• C. 692
• D. 690

Answer 1

Answer:

D. 690

Series: 650, 660, 669, 677, 684, ?

Step 1: Find the differences

Numbers	Difference
650 → 660	+10
660 → 669	+9
669 → 677	+8
677 → 684	+7

The pattern is decreasing by 1:
+10, +9, +8, +7, +6

Step 2: Add the next difference

684 + 6 = 690

Answer: 690