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,
[tex]2x+5y\le 800[/tex]
Due to the demand, they need to load at least 300 laptop computers, so
[tex]x\ge 300[/tex]
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
[tex]P=\$(225x+280y)[/tex]
Plot the system of inequalities (see attached diagram)
[tex]2x+5y\le 800[/tex]
[tex]x\ge 300[/tex]
The maximum profit will be at on of three vertices of the common region:
[tex]P(300,0)=225\cdot 300+280\cdot 0=\$67,500\\ \\P(300,40)=225\cdot 300+280\cdot 40=\$78,700\\ \\P(400,0)=225\cdot 400+280\cdot 0=\$90,000[/tex]