Which of the following numbers will replace the question mark (?) in the given series?
31, 33, 37, 43, 51, ?
Correct Answer :
61
Solution :
The correct answer is 61.
To find the missing number in the given series, let us analyze the pattern of differences between consecutive terms:
Notice that the difference between adjacent terms increases by 2 each time (a sequence of consecutive even numbers: 2, 4, 6, 8, ...).
Following this pattern, the next difference to add to 51 should be 10:
Therefore, the number that replaces the question mark (?) in the series is 61.
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