What will come in the place of question mark (?) in the following number series?
2, 3, -1, 8, -8, ?
Show answer & explanation
Correct answer: B
Explanation
Series: 2, 3, −1, 8, −8, ?
3 − 2 = 1
−1 − 3 = −4
8 − (−1) = 9
−8 − 8 = −16
Differences: 1, −4, 9, −16
The differences are perfect squares with alternating signs: (+1²), (−2²), (+3²), (−4²)
So, the next difference should be: (+5²) = +25
The missing number is:
−8 + 25 = 17
Hence, the correct answer is option (2).