You can trim the grass using a lawnmower at a rate of 80 square feet per minute. You can use a string trimmer at a rate of 20 square feet per minute. The yard has an area of 2800 square feet. If you use the trimmer for 20 minutes, how many minutes will you use the lawnmower? a 60 b 80 c 50 d 30

Mathematics · High School · Tue Nov 03 2020

Answered on

The answer is D ( 30 min ) .

Explanation : By using string trimmer 20 sq. feet per min.

1 min. = 20 sq. feet

20 min = 400 sq. feet 

Rest 2,800 - 400 = 2,400 

By using Lawnomower = 80 sq. feet per minute 

for find the time for 2,400 we divide 2,400 by 80 : 

2,400 / 80 = 30 

So 30 minute will we use the lawnmower.