Question 20
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Five years from now the ages of A and B will be in the ratio 3 : 4. Five years ago the ratio was 5 : 7. How old is A now?
- A 75 years
- B 55 years Correct
- C 45 years
- D 60 years
Correct Answer: Option B
4(a + 5) = 3(b + 5) → 4a = 3b − 5
7(a − 5) = 5(b − 5) → 7a = 5b + 10
From the first, a = (3b − 5)/4 → 7(3b − 5) = 20b + 40 → b = 75
a = 55
Answer: 55 years
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