Multiple choice

Seven years ago, the ratio of the age of A to that of B, was 5: 9. C is 12 years older than A and 12 years younger than B. What is C’s present age?

  1. 47 years

  2. 49 years

  3. 41 years

  4. 43 years

  5. 54 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let A and B be present ages. 7 years ago: (A-7)/(B-7)=5/9, so 9(A-7)=5(B-7), giving 9A-63=5B-35, or 9A=5B+28. C is A+12 and also B-12, so A+12=B-12, giving B=A+24. Substituting: 9A=5(A+24)+28=5A+120+28=5A+148, so 4A=148, A=37. C=A+12=37+12=49. C is 49 years old.

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