For the first store, let's calculate what he paid. Since he saved 75% and saved $15, we can calculate his expense as being
[tex] \frac{15}{0.75} - 15= 5[/tex]
So $5 in the first store.
For the next store we can calculate his expense by the rewriting 85% as 0.85 and calculate it as so
[tex] \frac{17}{0.85} = 20[/tex]
So $20 in the second store. Finally we can add the two together
[tex]20 + 5 = 25[/tex]
So Matt spent a total of $25 on the two stores
