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**Alexa****Guest**

Question i:

The other day I was in a department store, when i saw a shirt i liked that was on sale. It was marked "20% off". I decided to buy two. The person behind the till did some mental calculations. he said, "20 % off each shirt, that will be 40% off the total price."

(i) Explain clearly and fully what u would say to the shop assistant to convince him that an error has been made.

(ii)Also explain how the error should be put right.

I HAVE 5 DAYS UNTIL ITS DUE PLEASE HELLP!

**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,664

Percent is "per hundred", so it is still 20% off the total price.

For help in explaining, read Math Percentages

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**alexa****Guest**

wait i dont get it if there are two shirts wouldnt it make it 40 percent off

as their are two 20 percent offs?

**JaneFairfax****Member**- Registered: 2007-02-23
- Posts: 6,868

Alexa wrote:

(i) Explain clearly and fully what u would say to the shop assistant to convince him that an error has been made.

(ii)Also explain how the error should be put right.

I would probably say nothing to the shop assistant, but just pay the marked price less 40% and leave the shop quickly before the shop assistant discovers his error!

Let me explain why.

Okay, suppose each shirt costs 10 euros. A 20% reduction is a reduction of 20 ∕ 100 × 10 = 2 euros, so each shirt now costs 10 − 2 = 8 euros. I buy two shirts, which should cost me 16 euros. Now, if there were no reduction, I would have to pay 20 euros instead. The percentage difference is therefore (20 − 16) ∕ 20 × 100% = 20%, same as for just one shirt.

In fact, no matter how many shirts I buy, the percentage difference will always be 20%.

But, if the shop assistant wants to knock off 40% for two shirts, this would be a reduction of 40 ∕ 100 × 20 = 8 euros which means I am only charged 20 − 8 = 12 euros! This would be less than I should have paid! So why should I complain

*Last edited by JaneFairfax (2007-03-19 20:02:42)*

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,664

With **that shopkeeper** we could buy 5 shirts for 100% off, and no cost! (What would happen if we bought 6 shirts?)

The boss would sure be upset.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**alexa****Guest**

yeh i guess lol!

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