The percentage of the tip is 16%. This is computed by summing up all the bills, 23.59 + 40.65 + 30.50 + 15.68, which is equal to $110.42. Then $17.67 will be divided by $110.42, which is equal to 0.16000. After than to get the percentage we have to divide the 0.1600 by 100, which is equal to 16%.