we know that
Lisa paid [tex]\$43.95[/tex] for [tex]16.1[/tex] gallons of gasoline
so
by proportion
Find the cost of [tex]1[/tex] gallon of gasoline
[tex]\frac{43.95}{16.1}\frac{\$}{gal}=\frac{x}{1}\frac{\$}{gal} \\ \\x*16.1=43.95\\ \\x=43.95/16.1\\ \\x=\$2.73[/tex]
therefore
the answer is
The cost per gallon is equal to [tex]\$2.73[/tex]