Question

10 years ago the age of the father was 5 times that of the son. 20 years hence the age of the father will be twice that of the son. present age of the father (in years) is

• A. $40$
• B. $45$
• C. $60$
• D. $70$

Answer 1

Answer: (C)

$60$

Let the age of father be a and son be b
Then, 10 years ago:
$(a-10)=5(b-10)$ ........... (i)
After 20 years:
$(a+20)=2(b+20)$
$b=\frac{a-20}{2}$
Put the value of b in eqn(i)
$(a-10)=5(b-10)$

$a-10=5(\frac{b-20}{2}-10)$

$2a-20=5b-200$
$3a=180$
$a=60$