Multiple choice

A, B and C are students in a college. The average age of A and B is equal to 32. If B was replaced by C, then the average is equal to 34. If B's age 3 years hence is 37, then find the difference in ages of A and B two years ago.

  1. 2 years

  2. 6 years

  3. 4 years

  4. 8 years

  5. 10 years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(A+B)/2 = 32 => A+B = 64. (A+C)/2 = 34 => A+C = 68. B+3 = 37 => B = 34. A = 64 - 34 = 30. C = 68 - 30 = 38. A two years ago = 28. B two years ago = 32. Difference = 4.

AI explanation

The combined age of A and B is 2 times 32, which equals 64. The combined age of A and C is 2 times 34, which equals 68. B's current age is 37 minus 3, which is 34. Because A plus B equals 64, A's current age is 64 minus 34, which equals 30. Two years ago, A was 28 and B was 32, so the difference in their ages is 32 minus 28, resulting in 4 years.

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