Question

Edward cleaned a windowpane with a width of 5 feet and a length of 3 feet in 1/4 of an hour. What is the speed, in square feet per hour, at which Edward cleaned the pane?

Answer 1

`60\ (ft^2)/(h).`

Explanation:

If a windowpane is of the width of 5 feet and the length of 3 feet, then the area of this windowpane is

`A_(windowpane)=\text{length}\cdot \text{width}=3\cdot 5=15\ ft^2.`

If Edward cleaned a windowpane in 1/4 of an hour, then he cleaned 15 square feet in 1/4 of an hour. Thus, the speed at which Edward cleaned the pane is

`(15)/((1)/(4))=15\cdot 4=60\ (ft^2)/(h).`