Multiple choice

Find the missing term (?) in the following series: 5, 14, 30, 55, 91, ?

  1. 100

  2. 135

  3. 150

  4. 140

  5. 130
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D Correct answer
Explanation

The differences are 9, 16, 25, 36. These are squares of 3, 4, 5, 6. The next difference should be 7^2 = 49. 91 + 49 = 140.

AI explanation

The differences between the consecutive terms of the series are calculated as 14 minus 5 equals 9, 30 minus 14 equals 16, 55 minus 30 equals 25 and 91 minus 55 equals 36. These differences form a perfect square series of 9, 16, 25 and 36, which corresponds to the squares of 3, 4, 5 and 6. The next number in this difference pattern will be the square of 7, which is 49. Adding this 49 to the last term of the given series, 91 plus 49 equals 140. The required missing term is 140.

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