Question

Daniel works for a pest control company and is spraying all the lawns in a neighborhood. Each lawn in a neighborhood is approximately 0.2 acres in size and takes the same amount of time to spray. He started at the first house at 9:00 AM and the sixth house at 10:00 AM, and Daniel sprays 21 houses in total. How many minutes will it take Daniel to spray all of the lawns in the neighborhood?

Answer 1

252 minutes

Explanation:

All lawns are the same size, so it doesn't matter the exact size of the each lawn. Ignore the 0.2 acre size.

He started the first house at 9:00 AM and the sixth house at 10:00 AM.

Read the sentence above carefully. He started the first lawn at 9:00 AM. Since he started the sixth lawn at 10:00 AM, that means he finished the fifth lawn at 10:00 AM. In 1 hour, from 9:00 AM to 10:00 AM, he did 5 lawns.

1 hour = 60 minutes

60 minutes per 5 lawns = 60/5 minutes/lawn

which can be reduced to

12 minutes per lawn

His unit rate is 12 minutes/lawn.

Now you multiply his unit rate by the number of lawns, 21 of them, to find the number of minutes to spray 21 lawns.

12 minutes/lawn * 21 lawns = 252 minutes

Answer: 252 minutes