For this case, the first thing we must do is define variables:
x: cost of Five Stars notebooks
y: cost of CVS notebooks
We now write the system of equations:
x = y + 4
8x = 10y + 16
Solving the system of equations we have:
x = 12 $
y = 8 $
Answer:
Five Stars notebooks = $ 12
CVS notebooks = 8 $