Question

A hallway measuring 90 feet x 7 feet requires 1/2 a fluid ounce of cleaning solution per square foot. How much cleaning solution is required to clean the hallway

Answer 1

90ft * 7ft * (1/2 oz/ft^2) = 90*7*(1/2) oz

Note how the ft^2 cancel out, just leaving oz in the result. Watch the units, and they will help you decide how to multiply or divide the ratios.

Answer 2

315