[Part A] Answer: $1,250
Explanation:
We are given that the first 400 boxes are $1.75 each, then it is $1.25 each beyond that. They bought 840 boxes.
The first 400 are $1.75, then the last 440 are $1.25 since 800 - 400 = 440.
We will multiply the cost by the number, then add them together for the final total.
[Part B] (400 * $1.75) + (440 * $1.25) = $700 + $550 = $1,250