Question

The ages of sonu and Monu are in the ratio 7 : 5. Ten years hence, the ratio of their ages will be 9 : 7. Find their present ages.

Answer 1

It is given that the ratio of the ages of Sonu and Monu is 7: 5. 
Let the present ages of Sonu and Monu be 7x and 5x years. 
After ten years:

Age of Sonu = 7x + 10 years

Age of Monu = 5x + 10 years

According to the question,

\[\frac{7x + 10}{5x + 10} = \frac{9}{7}\] or 49x + 70 = 45x + 90

or 49x − 45x = 90 − 70

or 4x = 20

or x = 5

∴ Present age of Sonu = \[ 7 \times 5 = 35\text{ years }. \]

Present age of Monu = \[ 5 \times 5 = 25\text{ years }. \]