Question

A father is four times as old as his daughter. In 6 years, he will be three times as old as she is. How old is the daughter now?

Answer 1

The daughter is `12` years old.

Explanation:

We shall consider the father´s age as `x` and the daughter´s age as `y`. From the details, we can write these two equations:

`x=4y`
`x+6=3(y+6)`

Simplify the second equation by opening the brackets.

`x+6=3y+18`

Subtract `6` from both sides.

`x=3y+12`

Using the value of `x` from the first equation, substitute `x` in the simplified second equation with `color(red)(4y)`.

`x=3y+12`

`color(red)(4y)=3y+12`

Subtract `3y` from both sides.

`y=12`