Question

An office supply store recently sold a black printer ink cartridge for ​$18.99 and a color printer ink cartridge for ​$22.99. At the start of a recent fall​ semester, a total of 36 of these cartridges was sold for a total of ​$723.64. How many of each type were​ purchased?

Answer 1

Explanation:

Let x be the number of black ink cartridges sold and y be the number of color ink cartridges sold. We know that:

x + y = 36 (total number of cartridges sold)

18.99x + 22.99y = 723.64 (total amount of money earned)

We can use the first equation to solve for one variable in terms of the other and substitute that expression into the second equation to get a single equation in one variable, which can then be solved. For example:

y = 36 - x

18.99x + 22.99(36 - x) = 723.64

18.99x + 827.64 - 22.99x = 723.64

-4x = -104

x = 26

So, 26 black cartridges were sold and 36 - 26 = 10 color cartridges were sold.