Elena is now four times as old as Lizette. Five years ago, the sum of their ages was 45. How old is each now?
Call the present ages of Elena and Lizette
Substitute the first into the second and rearrange:
There are 2 people and 2 periods of time (past and present)
Choose a variable and write an expression for the age of each person for each period of time..
Lizette is younger, so let her age be
Elena is four times as old, so her age is
The sum of their ages
Write an equation to show this:
So, Lizette is
It all checks out!.