1/4 of a gallon of paint covers 1/12 of a wall
We can solve this using the Direct Rule of Three, as follows:
Paint Wall
1/4 1/12
x 1
1/12 * x = 1/4 * 1
x/12 = 1/4
12 is the LCM
Multiplying by 12 at both sides, we have:
x/12 * 12 = 1/4 * 12
x = 12/4
Manu will need 12 quarts of paint for the entire wall.
We can also say that Manu will need 3 gallons of paint for the entire wall.