Question

If 1/2 gallon of paint covers 1/5 of a wall, then how much paint is needed for the entire wall

Answer 1

2 1/2 gallons of paint.

If 1/2 gallon covers 1/5 of the wall, multiply 1/2 gallon by 5 to find how much is needed to cover 5/5, or the entire wall. You get 5/2. Now, simplify. 5/2 = 2 1/2 gallons of paint.