Answer :
Given:
[tex]10x+5y=80[/tex]Here x represents the number of pizzas and y represents the number of sandwiches.
Buy 3 pizas:
Substitute x=3 in the given expression, and solve for y.
[tex]\begin{gathered} 10x+5y=80 \\ 10\times3+5y=80 \\ 5y=80-10\times3 \\ y=\frac{80-30}{5} \\ y=\frac{50}{5} \\ y=10 \end{gathered}[/tex]Thus, you can buy 10 sandwiches if you buy 3 pizza.
Assume you buy 6 pizzas.
Substitute x=6 in the given expression.
[tex]\begin{gathered} 10x+5y=80 \\ 10\times6+5y=80 \\ 5y=80-10\times6 \\ y=\frac{80-60}{5} \\ y=\frac{20}{5} \\ y=4 \end{gathered}[/tex]Thus, you can buy 4 sandwiches if you buy 6 pizzas.