Mr X is 40 years old and Mr Y is 60 years old. How many years ago was the…
2020
Mr X is 40 years old and Mr Y is 60 years old. How many years ago was the ratio of their ages 3:5?
- A.
15 years
- B.
10 years
- C.
20 years
- D.
30 years
Attempted by 37 students.
Show answer & explanation
Correct answer: B
Let the required number of years ago be t. Then Mr X's age was 40 - t and Mr Y's age was 60 - t. According to the question, (40 - t)/(60 - t) = 3/5. Cross-multiplying: 5(40 - t) = 3(60 - t), so 200 - 5t = 180 - 3t. Hence 20 = 2t and t = 10. Therefore, the ratio of their ages was 3:5 ten years ago.