Answer:
$9.00
Step-by-step explanation:
Given that $1.8 is 20% of the breakfast cost.
-We can use proportions to find the 100% cost of the breakfast before the tip.
-Let x be the full breakfast cost:
[tex]0.2=1.8\\1.0=x\\\\0.2x=1.8\times 1.0\\\\\\x=\frac{1.8}{0.2}\\\\=9[/tex]
Hence, the full breakfast cost is $9.00 before the tip.