Question 1094516
<br>The required 45 gallons is a multiple of 5 but not of 7; so if you buy 5 gallon cans you can buy exactly the amount you need, but if you buy 7 gallon cans then you will need to buy more than you need.<br>
9 5-gallon cans makes the required 45 gallons.  To get 45 gallons with 7-gallon cans, you will need to buy 7 cans, giving you 49 gallons.  So you will have paint left over; however, you still spend less buying 7 7-gallon cans for $17 each than you would by buying 9 5-gallon cans for $15.50 each.<br>
I will assume you can figure out exactly how much you will save...