“My friends and I were on a beer run and noticed that the cases were discounted 10%. Since it was a big party, we bought 2 cases. The cashier multiplied 2 times 10% and gave us a 20% discount”
I can’t see anything wrong with this. If she gave a 20% discount for two cases wouldn’t it come out to 10% for each case? 
=“http://home.tiac.net/~cri/2007/amongus.html”
The original discount was 10% off, or 0.9x, where x is the cost of one case. If you purchased 2 cases at 10% discount, the total is 0.9(2x), or 1.8x. What she gave you was 0.8(2x), or 1.6x. So you made out, is what I’m saying.
Substitute 50% instead of 10% in your above scenario and see if it still makes sense.
http://home.tiac.net/~cri/2007/amongus.html
Here’s the link. Agree with **syzygy **- she could have multiplied the dollar discount for one case by two and been alright, but she multiplied the discount percentage by two and applied it to both cases.
Say regular price of a case is $10.
10% off each case makes the price $9, time 2 equals $18 for both cases.
20% off 2 cases makes the price $8 + $8, or $16 for both cases.
The cashier screwed up. You multiply the percentage off times the total price, not the number of cases. If you’d bought 10 cases, would she have given them to you for free (10% off times 10 cases = 100% off?)
Or better yet, just buy 10 cases next time.
I’d ask the cashier what the discount would be if I bought 10 cases – or, better still, more than 10 cases.
Alternatively, if you didn’t want to be too greedy, you could just but 9 cases for the price of one.
The discount percentage should not increase with the number of cases as you describe; if it did, then 10 cases would mean you’d get 100% off, i.e. a shitload of beer absolutely free of charge.
If you buy each case separately (for 10% off), that’s the same as buying both cases together for 10% off of the grand total.
2 * (0.9X) = 0.9 * (2X)
Where X = the regular price of a case of beer.
As Syzygy noted, if you got 20% off for buying two cases, you got an extra good deal.
I think I get it Bup. She applied a 20% discount to each case!
Thanks All. They say that the mind is the first thing to go…
:smack:
Buy 100 cases, get a free store!
I had a friend back when I was 20 and he was 19. We were having lunch at a restaurant/bar. On a whim that the waitress wouldn’t card him, he ordered a beer. She did card him, but she goofed on the subtract/borrow procedure when she subtracted 1965 from 1984 and got 21.
I then ordered one (before we figure out her mistake). But 1984-1964 is more easily seen to be 20, so no beer for A.
Take comfort: you might be wrong, and it was actually looks that were the first to go. 
Just like my students - still doesn’t get it!
Because of the way multiplication works, yes, she did. But only incidentally.
Am I being whooshed? He got it.
Next time do the math before you drink the two cases. 
So if you buy 10 cases, they’re free!
What happens when you buy 11 cases? The mind boggles.
What if you get 11 cases? Reminds me of Tippy Turtle.