Answer:
Maggie is 11 years old
Step-by-step explanation:
let m be Maggie and b be her brother.
[tex]m+b=59[/tex]
[tex]b=4m-6[/tex]
substitute for b.
[tex]m+4m-6=59[/tex]
[tex]5m-6=59[/tex]
add 6 to both sides
[tex]5m=55[/tex]
divide by 5 on both sides
[tex]m=11[/tex]
double check by finding the brother's age by substituting for m
[tex]11+b=59[/tex]
[tex]b=48[/tex]
