Multiple choice

One year ago, a man was 7 times as old as his son. Now, his age is equal to the square of his son's age. The present age of the man is

  1. 36 years

  2. 49 years

  3. 64 years

  4. None of the above
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A Correct answer
Explanation

Let son's age one year ago be x. Man's age = 7x. Present ages: son = x+1, man = 7x+1. Given 7x+1 = (x+1)^2. 7x+1 = x^2 + 2x + 1. x^2 - 5x = 0. x=5. Man's present age = 7(5)+1 = 36.

AI explanation

Let the son's present age be x, making the man's present age x squared. One year ago, the man's age was x squared minus 1 and the son's age was x minus 1, giving the equation x squared minus 1 equals 7 times x minus 1. Factoring the difference of squares yields x plus 1 times x minus 1 equals 7 times x minus 1, so x plus 1 equals 7 and x equals 6. The present age of the man is 6 squared, which is 36 years.

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