Answer:
400 laptop computers and 0 desktop computers
Step-by-step explanation:
Let x be the number of laptop computers and y be the number of desktop computers.
Laptop computer takes up 2 cubic feet, so x laptop computers take up 2x cubic feet of space. Desktop computer take up 5 cubic feet of space, so y desktop computers take up 5y cubic feet of space.
In total, they take 2x + 5y cubic feet.
The maximum capacity on the delivery truck is 800 cubic feet, thus,

Due to the demand, they need to load at least 300 laptop computers, so

They profit $225 on each laptop , then they profit $225x on x laptops. They profit $280 on each desktop computer, so they profit $280y on y desktop computers.
Total profit is

Plot the system of inequalities (see attached diagram)


The maximum profit will be at on of three vertices of the common region:
