The ratio of the present ages of A and B is 4 : 3. Ten years ago, the ratio was 3 : 2. What is the present age of A?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 40 years
Write the present ages with one unknown from the present ratio, and use the ratio of ten years ago to find it.
Let A \(=4k\) and B \(=3k\) years
\(\displaystyle \frac{4k-10}{3k-10}=\frac{3}{2}\)
\(2(4k-10)=3(3k-10)\), so \(8k-20=9k-30\) and \(k=10\)
A \(=4\times10=40\) years