In 10 years, A will be twice as old as B was 10 years ago. If A is now 9 years…
2026
In 10 years, A will be twice as old as B was 10 years ago. If A is now 9 years older than B the present age of B is
- A.
39 years
- B.
50 years
- C.
60 years
- D.
55 years
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Show answer & explanation
Correct answer: A
Let A and B be the present ages of A and B.
Equations:
A + 10 = 2 × (B − 10) — because in 10 years A will be twice as old as B was 10 years ago.
A = B + 9 — because A is 9 years older than B now.
Substitute A = B + 9 into the first equation:
(B + 9) + 10 = 2(B − 10)
Simplify: B + 19 = 2B − 20
Rearrange: 39 = B, so B = 39 years.
Therefore, the present age of B is 39 years. Then A = B + 9 = 48 years.