Question

Carlos is 8 years older than Maria. 4 years ago maria was two thirds as old as Carols. How old are they?

Answer 1

Maria is `28` and Carlos is `36`.

Explanation:

I call the age of Carlos today `C` and the one of Maria `M`.

The first relationship is

`C=8+M`

the second relationship is that

`M-4=2/3C`.

I substitute the first in the second

`M-4=2/3*(8+M)`

`M-4=16/3+2/3M`

multiplying by 3 both sides

`3M-12=16+2M`

`M=16+12`

`M=28`

and `C` is

`C=8+28=36`.

Just to verify, Carlos is 8 years older of Maria (he is 36 and Maria is 28) and four years ago Maria was 24 that is two third of the age of Carlos.