the question:-

I am four times as old as my daughter. She was born when I was 39, how old am I now?

I have worked out the answer is 52, just by using multiples of 4 etc.

My problem is she has to work it out using algebra and show her workings out. Ive tried but come to a dead end.

I would like help asap as homework has to be in tomorrow.

thanks

Suzibel