Saturday, 19 January 2008

Puzzle of the Week

When a secondhand bookstore holds a sale with a 10 percent reduction in prices, it makes an 8 percent profit on each book sold. What was the profit before the sale?

20 comments:

Julie Nemitz said...

Um, 18%?

Claire EJ said...

Is there VAT?? LOL

Mariann Mäder said...

8.8888888%

8% profit is on 90% of the original book price
8.888888 % is on 100% of the original book price

Melissa Hicks said...

No VAT sweetie :) It is a straight mathematical puzzle and neither Julie or Mariann are correct yet :)

I will point out that I didn't get it right when I tried it either :)

Claire EJ said...

I'm useless at these things which is why I went for the humorous answer...I'll go 2%

Melissa Hicks said...

To be honest I'm waiting for Nate the Teacher or Karen the Engineer (or even Tracy the ex-engineer) to figure this one :) :)

I promise the next wont be mathematical .....

Karen R said...

I'm much better at figuring up the sales tax. 18% was my instictive guess, but Mariann's rings with a bit of truth, too. 8.1%?

Melissa Hicks said...

Well according the answer on the back its neither .....

Natalie Mikesell said...

My first thought is 17.2% But I think that is wrong....I am not good with percentages

Denise Hicks said...

I'ii Say 10%

Stephanie Flynn said...

I agree with Natalie....17.2%. All of the amount that was discounted was profit lost, so add the lost profit fromt he sale to the remaining 8% of profit and you get your total profit. I chose an original book price of 100. So the sale price was 90. 8% of 90 is 7.20 plus the 10 you took off making 17.20 (equal to the percent since I started with 100)

Melissa Hicks said...

Do you want the written answer or do you want to keep on trying?

Mariann Mäder said...

I started out thinking somewhere along this line, too, but then tried to go the simpler way... Then I thought that the 10% deduction was not a deduction from the profit, but from the overall price so you couldn't consider the full 10% as profit...

Natalie Mikesell said...

Okay, I want the answer :) I tried it another way, and still could not come up with a better answer. This one has me stumped!!

Trish Froggatt said...

Nothing - because you can't make a profit until the book is sold????

Stephanie Flynn said...

Oh good answer Trish! You are most certainly correct!

Claire EJ said...

Pure logic..I bet she's right too!

Melissa Hicks said...

Nah - as I said this is a mathermatical puzzle.

Oh the answer - which makes my brain hurt by the way - is:

Not 10% + 8% = 18%.

If 90% of the original price is 108% of what a book costs the store, then 100% of the original price is 108% x 100/90 = 120% of what a book costs the store and there answer is 20%

Now would someone put that in English for me?

Claire EJ said...

Not a hope.

Stephanie Flynn said...

I still like Trish's answer.....it is in plain Englis correct as well.

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