a painter bought 12 gallons of paint to paint two rooms. one room is twice the size of the other and requires 3 coats of paint. the smaller room requires only 2 coats. the client decided not to paint the second room after all. how many gallons of paint will the painter have to return?

3 gallons of paint

Step-by-step explanation:

Various data is missing, but I think it can be solved with the following assumptions:

The first thing is to assume that 12 gallons was the exact amount needed for the two rooms.

If so, we can say the following where x is the size of the smallest room:

Room 1: It is 2 * x and needs 3 coats of paint, so there would be 6 * x left

Room 2: is x and uses 2 coats of paint therefore 2 * x

The paint sum would be as follows:

6 * x + 2 * x = 8 * x

8 * x = 12

x = 12/8 = 3/2

So:

Room 1: 6 * 3/2 = 9, 9 gallons of paint needed

Room 2: 2 * 3/2 = 3, 3 gallons of paint needed

Room two is the unpainted one so 3 gallons of paint was returned.