Question

What should come in place of the question mark (?) in the given series? 673 670 664 655 643 ?

• A. 632
• B. 625
• C. 628
• D. 630

Answer 1

Answer:

C. 628

Look at the pattern in differences:

• 673 → 670 = −3

• 670 → 664 = −6

• 664 → 655 = −9

• 655 → 643 = −12

The differences are increasing by −3 each time.

So next difference = −15

643 - 15 = 628

Answer: 628