Crystal earns $5.50 per hour mowing lawns.
a. choose the rule that describes how the amount of money m earned is a function
of the number of hours h spent mowing lawns.
b. how much does crystal earn if she works 3 hours and 45 minutes?

The solution to the problem is as follows:

Let m be the rate Crystal earns per hour on mowing the lawns.

m = 5.5h 

Since:

rate = quantity / time

quantity (earnings) = 5.5 *3.75 = $20 and 62.5 cents 

Therefore, she earns $20 and 62.5 cents in 3 hours and 45 minutes.

I hope my answer has come to your help. God bless and have a nice day ahead!