Part A:
if the price is $65 and if 40% is off so Li should pay 60% of it.
So 60% of $65 is:
60/100 = ?/65
? is the sale price:
65*60/100 = $39
Part B:
if he has 10% coupon for off then he should pay 90% of $39:
90/100 = ?/39
so ? is the answer:
39*90/100 = $35.1 :)))
I hope this is helpful
have a nice day