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Basic Mathematics MCQs
Q
Which number is wrong in the series: 1, 2, 6, 15, 31, 56, 91.
AA. 31
BB. 91
CC. 56
DD. 15
Correct Answer:
B. B. 91
Explanation:
The differences 1, 4, 9, 16, 25 are perfect squares. The wrong number in the series is 91, because the difference between 56 and 91 should be 36 (not 35) to maintain the pattern of perfect squares.