Multiple choice

A is twice as old as B. Ten years ago, A was four times as old as B. What are their present ages?

  1. 24 and 12

  2. 30 and 15

  3. 32 and 16

  4. 20 and 10
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let B's age be x, then A's is 2x. Ten years ago, (2x - 10) = 4(x - 10). Solving: 2x - 10 = 4x - 40, so 2x = 30, x = 15. Thus, B is 15 and A is 30.

AI explanation

Let B's present age be x years, making A's present age 2x years. Ten years ago, the equation is 2x minus 10 equals 4 times x minus 10. Solving this gives 2x minus 10 equals 4x minus 40, which simplifies to 2x equals 30, meaning x equals 15. Since A's age is 2x, their present ages are 30 and 15.

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