Multiple choice

Ram's father was 8 times as old as his son last year. Presently, his age is the square of his son's age. What is the difference between their ages?

  1. 20 years

  2. 30 years

  3. 36 years

  4. 42 years

  5. 40 years
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let son's age be x. Father's age = x^2. Last year: (x^2 - 1) = 8(x - 1). x^2 - 1 = 8x - 8. x^2 - 8x + 7 = 0. (x-7)(x-1) = 0. x=7 (x=1 is impossible). Father = 49, Son = 7. Difference = 42.

AI explanation

Let the son's present age be x years, making the father's present age x squared. Last year, the father's age was 8 times the son's age, giving the equation x squared minus 1 equals 8 multiplied by (x minus 1). This simplifies to x squared minus 8x plus 7 equals 0, yielding x equals 7. The difference between their ages is 7 squared minus 7, which is 49 minus 7, or 42 years.

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