Question

A company has to buy computers and printers. Each computer, x, costs $585 and each printer, y, costs

$385. If the company spends $7,575 and buys a total of 15 machines, how many of each did it buy?

Answer 1

x = 9, y = 6

Explanation:

Set up a system of equations.

x + y = 15

585x + 385y = 7575

substitute x = 15 - y in the second equation

585(15 - y) + 385 y = 7575

8775 - 585y + 385y = 7575

8775 - 200y = 7575

200y = 1200

y = 6

plug this y back into the first equation

x = 15 - 6 = 9

x = 9

Answer 2

x = 9

y = 6

Explanation:

Set up a system of equations

585x + 385y = 7575

x + y = 15

Solve for x for x + y = 15

x + y = 15 (Add -y to both sides)

x = -y + 15

Substitute -y + 15 for x in the first equation

585 (-y + 15) + 385y = 7575

-200y + 8775 = 7575 (Add -8775 to both sides)

-200y = -1200 (Divide both sides by -200)

y = 6

Substitute 6 for y in x = -y + 15

x = -6 + 15

x = 9