Question

Jackie's restaurant bill was $23. 50, and the tax was 8%. Jackie left a 20% tip on the post-tax bill. How much was the tip Jackie left? A) $4. 82 B) $5. 08 C) $6. 58 D) $7. 12​

Answer 1

well, the subtotal or pre-tax bill is $23.50, now let's add the 8% tax and

`\begin{array}ll \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{8\% of 23.50}}{\left( \cfrac{8}{100} \right)23.50}\implies 1.88`

so the post-tax bill is 23.50 + 1.88 = 25.38, and Jackie's tip is 20% of that

`\begin{array}c \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{20\% of 25.38}}{\left( \cfrac{20}{100} \right)25.38}\implies 5.076\qquad \approx 5.08`