Let x=money Sam earned this week
y=money Penni earned this week
We have 2 unknowns, so we must have 2 equations to solve this.
Eq. I: x=11(8) Sam earns $11/hr X 8hrs
Eq. II: x=(1/2)(30+y) Sam earned 1/2 as much of 30 dollars more than Penni
88=(1/2)(30+y) substitute 88 for x from Eq. I
88(2)=30+y multiply both sides by 2
176-30=y subtract 30 from both sides to isolate y
146=y solve for y
Therefore, Penni earned $146 this week.