Answer:
[tex]5(x-2.5)+3x=26.75\\x=4.90625$\\Where x is cost of sandwich.[/tex]
Step-by-step explanation:
Let cost of 1 sandwich[tex]=x[/tex]
Let cost of 1 drink[tex]=y[/tex]
[tex]3x+5y=26.75\\x-y=2.5 \Rightarrow y=x-2.5\\[/tex]
Now from the first equation
[tex]3x+5(x-2.5)=26.75\\8x-12.5=26.75\\8x=39.25\\x=4.90625[/tex]