Question

Five years ago, Rahul’s father was $5$ times as old as Rahul. But $5$ years from now, Rahul’s father will be $3$ times as old as his son. The present age of Rahul is

• A. $12$ years
• B. $10$ years
• C. $15$ years
• D. $18$ years

Answer 1

The correct option is C $15$ years

Let the age of rahul be 'x' and his father's age be 'y'.
So, According to the question
Five years ago ,
$(y-5)=5(x-5)$
$\Rightarrow (y-5)=5x-25$
$\Rightarrow y=5x-20$ ....(i)
Now, According to second part of the question,
$(y+5)=3(x+5)$ ....(ii)
From (i), Substitute the value of y in (ii) , we get
$(5x-20+5)=3x+15$
$\Rightarrow x=15$
So, the age of Rahul is 15 years.