Select the number from among the given options that can replace the question mark (?) in the following series.
62, 74, 80, 86, 95, ?, 158
Correct Answer :
113
Solution :
The correct answer is 113.
To find the missing number, we first calculate the differences between consecutive terms in the series:
62 → 74 → 80 → 86 → 95 → ? → 158
Differences:
74 - 62 = 12
80 - 74 = 6
86 - 80 = 6
95 - 86 = 9
? - 95 = d₅
158 - ? = d₆
So the sequence of differences so far is: 12, 6, 6, 9, d₅, d₆
Now, let's examine the ratios of consecutive differences (i.e., how each difference relates to the one before it):
6 ÷ 12 = 0.5
6 ÷ 6 = 1.0
9 ÷ 6 = 1.5
d₅ ÷ 9 = 2.0 (following the pattern)
d₆ ÷ d₅ = 2.5 (following the pattern)
The ratios form a clear arithmetic progression: 0.5, 1.0, 1.5, 2.0, 2.5, ... — increasing by 0.5 each time.
Using this pattern to find the missing differences:
d₅ = 9 × 2.0 = 18
d₆ = 18 × 2.5 = 45
Now we can verify:
? = 95 + 18 = 113
158 = 113 + 45 = 158 ✓
The complete series with all differences verified:
62 (+12) 74 (+6) 80 (+6) 86 (+9) 95 (+18) 113 (+45) 158
Therefore, the missing number that replaces the question mark is 113.
Access expert-curated educational resources and study materials—completely free.
Create, conduct, and manage professional online assessments with Mindyard. Perfect for teachers and institutes.
Copyright © 2026 Mindyard. All Rights Reserved.