i'll give brainliest this is due soon so yeahmPLSSSSSSSSS

Answer:
He pays taxes on the amount after the discount. So 10% of $40.50 versus $45.
Step-by-step explanation:
10% on $40.50 = $4.05
10% on $45.00 = $4.50
when you take 10% of $45, you're left with $40.50 because you'd do 40*10/100. when you go to add the 10% tax, you are no longer taxing $45, you're taxing $40.50 which is $4.05. 40.50+4.05=44.55