Carina is 5 year older than Marnie. Three years ago, she was twice as old as Marnie. how old are they now?

1 Answer
Jun 24, 2018

Marnie is 2 years old and Carina is 7 years old.

Explanation:

To solve our problem, let's write our information as equations. Carina is 5 years older than Marnie. Let Carnie be c and Marnie be m. Our equation would be c=m+5. Three years ago (c-3), Carina was twice as old as Marnie (2m). So, c-3=2m.

c=m+5
c-3=2m

After this, we can substitute c in the second equation for our entire first equation:

m+5-3=2m
m+2=2m
2=m

Next, let's put 2 into our first equation:

c=2+5
c=7

m=2, c=7