Answer: she would need 22 bags of fertilizer.
Explanation:
Gracie wants to create a rectangular-shaped garden in her backyard. The formula for determining the area of a rectangle is expressed as
Area = length × width
She has decided that the garden will be 20 by 16 feet long. This means the area of the rectangular-shaped garden is
Area = 20 × 16 = 320 ft²
If one bag of fertilizer only covers an area of 15ft², it means that the number of bags of fertilizer gracie will need for her garden is
320/15 = 21.33 bags