An item normally costs 40, but there is a 5 discount per item when buying 3 or more. What is the total cost of buying 4 items?

Because $4$ items is at least $3$, the discount applies to every item: each costs $40-5=35$ dollars. The total is $4\cdot35=140$ dollars, choice A. Choice C ($160) ignores the discount, $4\cdot40$. Choice B ($155) takes the $5 off only once, $160-5$. Choice D ($175) is $5\cdot35$, which uses the wrong number of items. The wording says the discount is per item, so it multiplies by the number of items, and the condition of buying three or more is satisfied.