1. He has to spend less than 115, so our current inequality is 115 > ???.
2. He has to spend $21 for each day, d, he drives, so that brings us to 115 > 21d. But we aren't done yet.
3. Because he has to spend $.10 for each mile driven and he's driving 250 miles, we have to multiple 250x.10, which brings us to 25. Leaving our answer at 115 > 21d + 25.
