The sum of the cubes of three consecutive natural numbers is divisible by

The sum of the cubes of three consecutive natural numbers is divisible by
  1. 26
  2. 25
  3. 9
  4. 7

Solution

Let the three consecutive natural numbers \((n-1), n, n+1\) where \(n \geq 2\) \(\therefore\) Sum of cubes of the three consecutive natural numbers is \((n-1)^3+n^3+(n+1)^3=3 n^3+6 n=3 n\left(n^2+2\right)\) For each value of \(n \geq 2\), the expression \(3 n\left(n^2+2\right)\) is divisible by 9 . Hence, option (c) is correct.

Asked in: AP EAMCET 2020 (21 Sep Shift 2)

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