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

1 Answer
Jul 7, 2016

Answer:

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.