The sum of the squares of two consecutive positive integers exceeds their product by 91. Find the integers?
Correct answer: A. 9, 10
- A. 9, 10
- B. 10, 11
- C. 11, 12
- D. 12, 13
Explanation
Let the consecutive positive integers be n and n + 1. Their square sum exceeds their product by n² + (n + 1)² - n(n + 1) = n² + n + 1 = 91, so n² + n - 90 = 0 and (n + 10)(n - 9) = 0; positivity gives n = 9, hence 9 and 10. The likely mistake is choosing b by adding the two integers or comparing the square sum without subtracting the product.
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