You can put this solution on YOUR website! Christian is 3 times as old as Marie.
c = 3m
Marie is 12 years younger than Christian.
m = c - 12
Replace c with 3m, from the first statement
m = 3m - 12
m - 3m = -12
-2m = -12
m = -12/-2
m = +6 is Marie's age
:
How old is Christian?
c = 3(6)
c = 18 is Christian's age
:
:
Check solutions in the 2nd statement
" Marie is 12 years younger than Christian."
6 = 18 - 12
