A simple algebraic word problem

Question

A movie star is four times as old as his daughter. However seven years ago he was eleven times

as old as she was. How old is the movie star?

Answer 1

Let's call the father's current age X

Let's call the daughter's current age Y

 

This means that currently, X=4Y...............(i)

 

Seven years ago, the father was (X-7) years old and the daughter was (Y-7) years old

 

If the father was 11 times as old as his daughter at the time, that leaves us with

 

(X-7)=11(Y-7)................(ii)

 

From equation (i), replace X with 4Y and substitute this into equation (ii)

 

i.e (4Y-7)=11(Y-7)

 

After expanding, you have 7Y=70 

So the daughter is 10 years old 

That means that her dad is 40 years old