Question

5 years ago a man was 7 times as old as his son. After 5 years he will be thrice as old as his son. Find their present ages.

Answer 1

Let the age of son be \(\frac{1}{7}\)x years, 5 years ago and that of father be x years

According to the question

\(\text{x}+10=3(\frac{1}{7}\text{x}+10)\)

Taking LCM of 1 and 7 = 7

\(\Rightarrow \frac{7\text{x - 3x}}{7}\) = 30 - 10

⇒ 4x = 140 

⇒ x = 35

So the present age of father = 35 + 5 = 40 years and that of son is \(\frac{1}{7}\)x + 5 = 5 + 5 = 10 years