Question

A student mows lawns on the weekends. It takes him 180 minutes to mow 4 lawns. What prediction can you make about the time he will spend this weekend if he has 12 lawns to mow?

It will take him 9 hours to mow 12 lawns.
It will take him 18 hours to mow 12 lawns.
It will take him 20 hours to mow 12 lawns.
It will take him 60 hours to mow 12 lawns.

Answer 1

It will take him 9 hours to mow 12 lawns.

Explanation:

We can use a proportion. We see that the answer choices are in hours, so let's first convert the given information to hours.

180 minutes × (1 hour)/(60 minutes) = 3 hours

180 minutes to mow 4 lawns = 3 hours to mow 4 lawns

Proportion:

3 hours is to 4 lawns as x hours is to 12 lawns

3/4 = x/12

4x = 3 × 12

4x = 36

x = 9

Answer: It will take him 9 hours to mow 12 lawns.