Question

Mrs. Kosko left $19.47 on the table in a restaurant after receiving the bill for $16.50. If there was no tax, what percent did she tip? (A) 15% (B) 13% (C) 17% (D) 18%

Answer 1

Take the cost of the bill and add the tip percentage of the bill. That is:

$cost = bill + (bill \times\% \: tip)$

or

$cost = bill(1 + \% \: tip)$

solve:

$19.47 = 16.50(1 + \% \: tip)$

$\frac{19.47}{16.50} = 1 + \% \: tip$

$1.18 = 1 + \% \: tip$

$\% \: tip = 0.18 = 18\%$

The tip was 18% of the bill.

Answer 2

She tipped 18 percent . 16.50x0.18= 2.97. 16.50+2.97= 19.47