First you need to find the area of the garden. The formula for that is A=bh.
the base is 15 and the height is 30. 15 x 30 = 450, making the area of the garden 450 feet.
Next you need to divide the area, 450 by the number of hours it took to install all the grass, which is 4. 450 divided by 4 is 112.5
Emily installed the grass at an average speed of 112.5 feet per hour.
