Which of the following numbers would replace the question mark (?) in the given number series? 2, 10, 30, ?, 130
A.58
B.68✓ Correct
C.78
D.48
Explanation
The series follows the pattern n×(n+1): 1×2=2, 2×5=10, 3×10=30, 4×17=68, 5×26=130. Differences: 8,20,38,62 — second differences: 12,18,24 (+6 each). So next difference = 38, giving 30+38=68.
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