How many gallons of each should be purchased?
1 Answer
You should buy 11 gallons of finishing paint and 17 gallons of primer. You will have half a gallon of primer left at the end.
Explanation:
Before solving the problem, I will give you some useful hints on a common quantity in math and science.
The value 450 in this problem is an example of a rate . It compares two quantities that have different units, such as square feet of area and gallons of paint. It does this in such a way that the chosen quantity of one of the units is one. This quantity is the "base" of the rate - the one that comes after the word "per", as in square feet per gallon.
What this means is the rate tells you how many square feet will be covered by each one gallon of paint.
In this question, you are told about the total amount of the other quantity (the square feet) that needs to be covered. To determine the correct number of gallons to use, you divide by the rate:
Now since you use 3 gal of primer for each 2 gal of finishing paint, the amount of primer is
Since you won't be able to buy half a gallon, but 17 gallons of primer.
