Question

A boy is now $a$ years old and his father is $5a$ years old. How old will the father be when the boy is $3a$ years old? How old was the father when the boy was born?

• A. $7a,4a$ years
• B. $4a,10a$ years
• C. $12a,3a$ years
• D. $15a,3a$ years

Answer 1

The correct option is A $7a,4a$ years

Difference of the age of boy and father $=5a-a=4a$

$\therefore$ The father's age when the boy is $3a$ years old $=3a+4a=7a$

When the boy was born, then the father's age $=4a$.