Question

Ashley and Kristin are selling wrapping paper for a school fundraiser. Customers can buy rolls of plain wrapping paper and rolls of shiny wrapping paper. Ashley sold 4 rolls of plain wrapping paper and 3 rolls of shiny wrapping paper for a total of $68. Kristin sold 9 rolls of plain wrapping paper and 2 rolls of shiny wrapping paper for a total of $77. What is the cost each of one roll of plain wrapping paper and one roll of shiny wrapping paper?

Answer 1

The cost of one roll of plain wrapping paper is $5 and one roll of shiny wrapping paper costs $16.

Step-by-step explanation:

Step 1; Assume that the cost of one roll of plain wrapping paper is $x and a roll of shiny wrapping paper costs $y. so we have the following equations from the given data

4x + 3y = 68, take this as equation 1.

9x + 2y = 77, take this as equation 2

Step 2; We multiply equation 1 with 2 and equation 2 with 3 so we can cancel out the variable y in both equations. By doing this we get

8x + 6y = 136, take this as equation 3,

9x + 2y = 77, this is equation 4.

If we subtract 4 from 3, we cancel out the y variable and can calculate the value of x.

-19x = -103 , x = $\frac{-95}{-19}$ = 5.

Step 3; Substituting this value of x in any of the previous equations we will get x's value. Here this value of y is substituted in equation 1.

4 (5) + 3y = 68, 20 + 3y = 68 , 3y = 48, y= 16.

So we have x = $5 and y = $16.