What should come in place of the question mark (?) in the given series?
670 668 671 666 673 662 676 ?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 656.
Series: 670, 668, 671, 666, 673, 662, 676, ?
Let's observe the pattern:
- 670 → 668 = −2
- 668 → 671 = +3
- 671 → 666 = −5
- 666 → 673 = +7
- 673 → 662 = −11
- 662 → 676 = +14
The negative differences are:
−2, −5, −11
- −2 → −5 = −3
- −5 → −11 = −6
- Next increase in magnitude = −9
- So, next negative difference = −20
Therefore:
- 676 − 20 = 656