Question

First estimate and then find the exact amount of both a 15% and a 20% tip on a restaurant bill of $86.08. To estimate the amount of a tip, round the price of the bill to the nearest $10.

a 15% tip is approximately$___
on a $86.08 bill a 15% tip is exactly___

A 20% tip is approximately $____
On a $86.08 bill, a 20% tip is exactly$____

Answer 1

Rounding 86.08 to nearest 10 is 90. 10% of 90 is 9, so 5% of 90 is 4.50, so the estimate of 15% of $86.08 is $13.50

Answer 2

The exact amount is 15% x $86.08 =0.15 x $86.08 = $12.91

Answer 3

Part 2, 20%:
Estimate: 10% of $90 is $9, so 20% of $90 is $18
Exact: 20% of $86.08 = 20% x $86.08 = 0.2 x $86.08 = $17.22