The price of the burger and fries is:
[tex]12+4=16[/tex]This is the cost at menu price, we need to find the discount by multiplying the cost by 20%:
[tex]16\times\frac{20\%}{100\%}=3.2[/tex]Subtract the discount to the price:
[tex]16-3.2=12.8[/tex]This is the price you will pay after the discount.
Now, to find the tip, multiply this price by 15% and add it to the price:
[tex]\begin{gathered} 12.8\times\frac{15\%}{100\%}=1.92 \\ 12.8+1.92=14.72 \end{gathered}[/tex]This is the bill by including the tip.
Finally, we need to find the sales tax by multiplying the bill by 7% and then add it to the bill:
[tex]\begin{gathered} 14.72\times\frac{7\%}{100\%}=1.03 \\ 14.72+1.03=15.75 \end{gathered}[/tex]So, the burger and fries cost $15.75
