I don’t know if its just me but i can’t see the picture, im really sorry :/
I am better at substitution, but you want to get the equations as similar as possible, but are the opposite, so you can cancel it out.
Answer:
B) is the correct answer because the 5 shirts are supposed to be LESS THAN 55, hence the less than symbol.
20,000, so that his interest rate will be lower and he will overall save $$$