I don’t get how they added to get the amount of money earned, I need help if you can explain how I can find the amount of money earned for 40 hours.

Answer:
330
Step-by-step explanation:
123.75 : 15= 8,25--> the money you earn in one hour.
8,25 x 10= 82,50--> the money you earn in 10 hours.
247,50 (30h) + 82,50 (10h)= 330 (40h)
:)