Multiple choice

After 12 years, A will be 3 times as old as B was 8 years ago. If A is 10 years older than B, then the present age of A is

  1. 30 years

  2. 35 years

  3. 33 years

  4. 40 years

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let A's age be a, B's age be b. a = b + 10. (a + 12) = 3(b - 8). Substitute a: (b + 10 + 12) = 3b - 24. b + 22 = 3b - 24. 46 = 2b, so b = 23. A = 23 + 10 = 33.

AI explanation

Let B's present age be b, which makes A's present age b + 10. After 12 years, A's age will be b + 22. According to the question, A's age after 12 years equals 3 times B's age 8 years ago, so b + 22 = 3(b minus 8). Solving this equation gives b + 22 = 3b minus 24, which means 2b = 46, making B 23 years old. Therefore, A's present age is 23 + 10, which is 33 years.

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