Multiple choice

Find the missing number in the series: 7,?, 63, 124, 215

  1. 26

  2. 19

  3. 28

  4. 21
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A Correct answer
Explanation

Pattern: 2^3-1=7, 3^3-1=26, 4^3-1=63, 5^3-1=124, 6^3-1=215. The missing number is 26.

AI explanation

The series follows the pattern of consecutive cubes minus one: 2 cubed is 8 minus 1 is 7, 3 cubed is 27 minus 1 is 26, 4 cubed is 64 minus 1 is 63, and 5 cubed is 125 minus 1 is 124. The missing term is 3 cubed minus 1, which is 26.

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