Respuesta :
Let:
x = Cost of one plain pizza
y = Cost of one soda
two friends went to a restaurant and ordered one plain pizza and two sodas. the bill totaled $15.95. so:
[tex]\begin{gathered} x+2y=15.95_{\text{ }} \\ \end{gathered}[/tex]later that day, five friends went to the same restaurant. they ordered 3 plain pizzas and 5 sodas. their bill totaled $45.90. so:
[tex]3x+5y=45.90[/tex]Let:
[tex]\begin{gathered} x+2y=15.95_{\text{ }}(1) \\ 3x+5y=45.90_{\text{ }}(2) \end{gathered}[/tex]From (1) solve for x:
[tex]x=15.95-2y_{\text{ }}(3)[/tex]Replace (3) into (2):
[tex]\begin{gathered} 3(15.95-2y)+5y=45.90 \\ 47.85-6y+5y=45.90 \\ -y=-1.95 \\ y=1.95 \end{gathered}[/tex]Replace the value of y into (3):
[tex]\begin{gathered} x=15.95-2(1.95) \\ x=12.05 \end{gathered}[/tex]Therefore, the price of one plain pizza is $12.05
