Multiple choice

2 years ago, John's age was 4 times that of his son. After 1 year, his age will be 3 times that of his son. What is the difference between their present ages?

  1. 16 years

  2. 18 years

  3. 24 years

  4. 20 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let J and S be present ages. (J-2) = 4(S-2) => J-2 = 4S-8 => J = 4S-6. (J+1) = 3(S+1) => J+1 = 3S+3 => J = 3S+2. 4S-6 = 3S+2 => S = 8. J = 4(8)-6 = 26. Difference = 26-8 = 18.

AI explanation

Let their ages two years ago be 4x and x, so their present ages are 4x + 2 and x + 2. After one year, the equation is (4x + 3) / (x + 3) = 3, which simplifies to 4x + 3 = 3x + 9, meaning x equals 6. Their present ages are 26 and 8, making the difference 18 years.

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