Using mental math, the approximate tip to leave for a bill of $81.79, if you tip 15% would be _____..

Question

a.
$8.20
b.
$10.30
c.
$12.30
d.
$16.40

Answer 1

To find an approximate tip of 15% for a bill of $81.79, you can break it down as follows:

1. A quick way to estimate 15% is to first calculate 10% and then add half of that for 5%.
2. 10% of $81.79 is approximately $8.18 (since $81.79 can be rounded to $81.80).
3. 5% is half of 10%, which would be about $4.09.

Now, add the two:

• 10% ($8.18) + 5% ($4.09) = approximately $12.27.

Thus, the closest option to our estimate of $12.27 is c. $12.30.