Martin needs 3.25 gallons of red paint for his small barn and 1.25 gallons of paint for his shed. He spends $81 on paint. How much does the paint cost per gallon?
You need to write 81= 4.5x, because 81 is the total price, and then you have to divide it by the total gallons of paint, which is 4.5. The solution is that each gallon is $18. This is only if its all the same type of paint.
