## Percentage fail

No, it’s not.

Submitted by: Anonymous

** Note: Some posts on Math-Fail are user-submitted and NOT verified by the admin of the site before publication. If you find this post to be distasteful, non-math related, ?or something worse?, then definitely leave a comment letting me know. Thanks very much! Mike **

(5.00 from 4 votes)
Loading ...
Leave a comment ?

## 3 Comments.

1. Many restaurants suggest tipping based on a pre-coupon / pre-discount total. The original bill would have been something like \$40 with a 50% discount in a county with 9% sales tax on prepared foods. (sales tax is calculated with regard to the subtotal pre-coupon amount in the case of a percentage decrease and added after the discount took place). Tip is often calculated against the pre-coupon,post-tax amount.

40*1.09 – .5*40 = 23.60 (total as it appears on check)
40*1.09*0.15 = 6.54 (suggested tip amount for 15%)
40*1.09*0.17 = 7.84 (suggested tip amount for 18%)
40*1.09*0.20 = 8.72 (suggested tip amount for 20%)

So, my guess was off by a few pennies somewhere. Perhaps the sales tax in the area isn’t exactly 9%, or perhaps it was a \$39.99 meal with a 50% off coupon, but you get the idea.

1  0

2. Uuuuuuuuuuuuuuuuuuuuuuuuuuuuu!!! tough guy!!!! thats just a customer copy….

1  0

3. It’s easier than jihkro’s solution. They got \$19.90 off, but calculated the tip based on the full amount. No VAT speculation needed.

0  0