Paper plates cost $8 per package and plastic utensils cost $5 per package. your supplier delivers 15 packages for a total cost of $90.

To find the total of what you sold for each package, you'll need to write two equations. Know that x = paper plate packages and y = utensil packages.
First, x + y = 15 shows that there has to be fifteen packages, and 8x + 5y = 90 shows the $ made from selling a certain number of packages.
Next, you can solve by substitution, so change x + y = 15 to y = 15 - x.

To find our x, substitute the y in 8x + 5y = 90 to get
8x + 5(15 - x) = 90
Distribute: 8x + 75 - 5x = 90
Combine the X's and subtract the 75: 3x = 15
Divide the 3: x = 5

Now with our x, we can put 5 into the original equation x + y = 15 to get 5 + y = 15. Subtracting the 5, we get y = 10.

So, you have delivered 5 paper plate packages and 10 utensil packages.