Multiple choice

The average of the squares of five consecutive positive integers is 66. Find the average of these five integers.

  1. 6

  2. 10

  3. 8

  4. 12
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the middle integer be n. Then the integers are n-2, n-1, n, n+1, n+2. Their squares are (n²-4n+4), (n²-2n+1), n², (n²+2n+1), (n²+4n+4). Sum = 5n² + 10. Average = (5n² + 10)/5 = n² + 2 = 66, so n² = 64, n = 8. The average of the five integers is n = 8. Option C is correct.

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