A bookseller sells his books at a 20% markup in price...

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A bookseller sells his books at a 20% markup in price. If he sells a book for $12.00, how much he did pay for it?

A. $14.40
B. $14.00
C. $10.00
D. $9.60
E. $5.00

The OA is C.

Please, can any expert explain this PS question for me? I have many difficulties to understand why that is the correct answer. Thanks.

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by EconomistGMATTutor » Tue Nov 28, 2017 8:47 am
Hello swerve.

Let's see your question.

The bookseller add the 20% to the price he paid for the book.

So, if x is the cost price then $$120\%\cdot x\ =\ 12\ dollars,$$ it implies that $$120\%\cdot x=\frac{120}{100}\cdot x=\frac{6}{5}\cdot x=12\ dollars\ \leftrightarrow\ x=\frac{60}{6}=10\ dollars.$$ So, the correct answer is C.

I hope this may help you to understand the question.

I'm available if you'd like a follow up.

Regards.
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by Brent@GMATPrepNow » Tue Nov 28, 2017 9:30 am
swerve wrote:A bookseller sells his books at a 20% markup in price. If he sells a book for $12.00, how much he did pay for it?

A. $14.40
B. $14.00
C. $10.00
D. $9.60
E. $5.00
Another approach is to test the answer choices

When testing the answer choices, it's a good idea to start with the MIDDLE answer choice.
If it turns out that value is too high, then you can test smaller values.
If it turns out that value is too small, then you can test bigger values.

Test C: The bookseller paid $10.00
20% of $10.00 = $2.00
$10.00 + $2.00 = $12.00
BINGO!

Answer: C

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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by Scott@TargetTestPrep » Sat Oct 05, 2019 3:40 pm
swerve wrote:A bookseller sells his books at a 20% markup in price. If he sells a book for $12.00, how much he did pay for it?

A. $14.40
B. $14.00
C. $10.00
D. $9.60
E. $5.00

The OA is C.

Please, can any expert explain this PS question for me? I have many difficulties to understand why that is the correct answer. Thanks.
We can create the equation:

1.2c = 12

c = 10

Answer: C

Scott Woodbury-Stewart
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[email protected]

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