We are doing a small group project and my group members and I are very confused. The project description:

Using the variables provided below, you are working with your group to make a recommendation to the township directors. Currently we mow the grass surounding the highway. A proposal was made by a landscaping company to cover the area with a wild flower that will not require mowing, but trimming periodically. It is your team's job to determine if we should plant the groundcover or if we should just continue to mow the grass by the highway.

Variables given:

Road length in miles - 5
Roadside Distance in yards (aka the width) - 20
Number of exits - 4
Exit size in yards - 50
Labor Cost per hour - $15
Cost of gas - $2.65
Mowing frequency on average - Every 10 days for nine months
Deck size of the mower - 30 inches

My group has already figured out the wild flower data, so I didn't include those variables. What we are struggling to figure out is how many hours it takes to mow, so that we can figure out how much money will be given as the labor cost ($15 x ___ hours). We have figured out that the area that is mowed, when the exits are taken away since they don't need to be mowed, is 172,000 square yards, and the teacher has confirmed that this is correct.

What we don't get is how to possibly figure out the time/hours it takes when all we are given are yards and measurements. The teacher mentioned something about calculating the "passes," or number of times the mower goes up and down the rows, but we don't get how that could help us find the time. Is it even possible? Your help is appreciated, especially since this is a graded project. Thank you so much!

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