Answer:
If Larry worked on Mrs. Grinnell's lawn for 3 hours, Mrs. Grinnell would owe Larry $108.
Explanation:
You have to find the total amount Larry would receive with $50 an hour:
$50*3=$150
Now, you have to calculate the amount with a 20% discount by calculating the 20% of $150 and subtracting that amount from $150:
$150*20%=$30
$150-$30=$120
Then, you have to calculate the 10% of $120 and subtract that amount from $120:
$120*10%=$12
$120-$12=$108
According to this, the answer is that if Larry worked on Mrs. Grinnell's lawn for 3 hours, Mrs. Grinnell would owe Larry $108.