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!