Given:
Amanda sold 13 rolls of plain wrapping paper and 12 rolls of holiday wrapping paper for a total of $208.
And,
Mofor sold 4 rolls of plain wrapping paper and 3 rolls of holiday wrapping paper for a total of $55.
Let, x be the cost of one roll of plain wrapping paper and y be the cost of one roll of holiday wrapping paper.
The equations are,
[tex]\begin{gathered} 13x+12y=208\ldots\ldots\ldots\text{.....}(1) \\ 4x+3y=55\ldots\ldots..\ldots\ldots\ldots\text{.}(2) \end{gathered}[/tex]Solve the equations,
[tex]\begin{gathered} 4x+3y=55 \\ 4x=55-3y \\ x=\frac{55-3y}{4} \\ \text{Put it in quation (1)} \\ 13x+12y=208 \\ 13(\frac{55-3y}{4})+12y=208 \\ \frac{715-39y}{4}+12y=208 \\ 715-39y+4(12y)=4(208) \\ 715-39y+48y=832 \\ 9y=832-715 \\ 9y=117 \\ y=\frac{117}{9} \\ y=13 \end{gathered}[/tex]Put the value of y in equation (2),
[tex]\begin{gathered} 4x+3y=55 \\ 4x+3(13)=55 \\ 4x+39=55 \\ 4x=55-39 \\ 4x=16 \\ x=\frac{16}{4} \\ x=4 \end{gathered}[/tex]Answer:
The cost of one roll of plain wrapping paper is x = $4.
The cost of one roll of holiday wrapping paper is y = $13.