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The price of a pastry when made fresh was $P.Each hour after the first

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The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post Updated on: 11 Aug 2017, 13:00
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Question Stats:

10% (01:34) correct 90% (01:20) wrong based on 49 sessions

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The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Lampard?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

Originally posted by DHAR on 01 Aug 2017, 08:16.
Last edited by DHAR on 11 Aug 2017, 13:00, edited 2 times in total.
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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 01 Aug 2017, 19:17
1
DH99 wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Julie?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

Who is Julie?!
Sorry, couldn't resist. Definitely studying too hard. They need a cross-eyed emoji.

Pastry price decreases by 20 percent for each hour after it is made. Call initial price P. Decrease of 20 percent = 1 - .20 = .80

Fresh out of oven = P
1 hour later = .80P
2 hours later = .64P (.80P * .80)
3 hours later = .512P (.64P * .80)

Lampard bought a pastry fresh and paid P.

His sister bought a pastry three hours later. She paid .512P

Price paid by Lampard’s sister was what percent less than that paid by Lampard?

Percent change = \(\frac{change}{original}\) * 100

Change is P - .512P = .488P

\(\frac{.488P}{1P}\) = .488 * 100, or

48.8% less

Answer D

I usually plug in values but it got to be a mess.

DH99 , you're working hard at posting all these questions. Kudos deserved and given.
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In the depths of winter, I finally learned
that within me there lay an invincible summer.

-- Albert Camus, "Return to Tipasa"

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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 01 Aug 2017, 20:25
genxer123 wrote:
DH99 wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Julie?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

Who is Julie?!
Sorry, couldn't resist. Definitely studying too hard. They need a cross-eyed emoji.

Pastry price decreases by 20 percent for each hour after it is made. Call initial price P. Decrease of 20 percent = 1 - .20 = .80

Fresh out of oven = P
1 hour later = .80P
2 hours later = .64P (.80P * .80)
3 hours later = .512P (.64P * .80)

Lampard bought a pastry fresh and paid P.

His sister bought a pastry three hours later. She paid .512P

Price paid by Lampard’s sister was what percent less than that paid by Lampard?

Percent change = \(\frac{change}{original}\) * 100

Change is P - .512P = .488P

\(\frac{.488P}{1P}\) = .488 * 100, or

48.8% less

Answer D

I usually plug in values but it got to be a mess.

DH99 , you're working hard at posting all these questions. Kudos deserved and given.


Thank you,I will recheck the question and correct Julie.I was trying to plug in numbers as well but I got 44%.

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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 01 Aug 2017, 20:27
DH99 wrote:
genxer123 wrote:
DH99 wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Julie?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

Who is Julie?!
Sorry, couldn't resist. Definitely studying too hard. They need a cross-eyed emoji.

Pastry price decreases by 20 percent for each hour after it is made. Call initial price P. Decrease of 20 percent = 1 - .20 = .80

Fresh out of oven = P
1 hour later = .80P
2 hours later = .64P (.80P * .80)
3 hours later = .512P (.64P * .80)

Lampard bought a pastry fresh and paid P.

His sister bought a pastry three hours later. She paid .512P

Price paid by Lampard’s sister was what percent less than that paid by Lampard?

Percent change = \(\frac{change}{original}\) * 100

Change is P - .512P = .488P

\(\frac{.488P}{1P}\) = .488 * 100, or

48.8% less

Answer D

I usually plug in values but it got to be a mess.

DH99 , you're working hard at posting all these questions. Kudos deserved and given.


Thank you,Edited Julie to Lampard.I was trying to plug in numbers as well but I got 44%.

Posted from my mobile device


Posted from my mobile device

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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 01 Aug 2017, 22:11
1
genxer123 wrote:
DH99 wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Julie?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

Who is Julie?!
Sorry, couldn't resist. Definitely studying too hard. They need a cross-eyed emoji.

Pastry price decreases by 20 percent for each hour after it is made. Call initial price P. Decrease of 20 percent = 1 - .20 = .80

Fresh out of oven = P
1 hour later = .80P
2 hours later = .64P (.80P * .80)
3 hours later = .512P (.64P * .80)

Lampard bought a pastry fresh and paid P.

His sister bought a pastry three hours later. She paid .512P

Price paid by Lampard’s sister was what percent less than that paid by Lampard?

Percent change = \(\frac{change}{original}\) * 100

Change is P - .512P = .488P

\(\frac{.488P}{1P}\) = .488 * 100, or

48.8% less

Answer D

Hi, genxer123: It's given Each hour after the first hour the price decreased by 20%.So, why it will not be: Say when we take p=100.
Fresh out of oven = P =100
1 hour later = 100 (same since Each hour after the first hour)
2 hours later = 80
3 hours later = 64
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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 02 Aug 2017, 11:20
1
DH99 wrote:
DH99 wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Julie?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %

genxer123 wrote:
Pastry price decreases by 20 percent for each hour after it is made. Call initial price P. Decrease of 20 percent = 1 - .20 = .80

Fresh out of oven = P
1 hour later = .80P
2 hours later = .64P (.80P * .80)
3 hours later = .512P (.64P * .80)

Lampard bought a pastry fresh and paid P.

His sister bought a pastry three hours later. She paid .512P

Price paid by Lampard’s sister was what percent less than that paid by Lampard?

Percent change = \(\frac{change}{original}\) * 100

Change is P - .512P = .488P

\(\frac{.488P}{1P}\) = .488 * 100, or

48.8% less

Answer D


DH99 wrote:
Hi, genxer123: It's given Each hour after the first hour the price decreased by 20%.So, why it will not be: Say when we take p=100.
Fresh out of oven = P =100
1 hour later = 100 (same since Each hour after the first hour)
2 hours later = 80
3 hours later = 64

DH99 , good question. I agree that the highlighted phrase is confusing.

After plugging in numbers as you did, the "percent less than" was \(\frac{(100 - 64)}{100}\) * 100 = 36 percent less.

That's not an option in the answer choices. Conclusion: I was wrong to think, "One hour passed, and AFTER THAT, the price decreased every hour, so first decrease hits at the end of the second hour."

So I thought about when "after the first hour" could begin to toll. When does "the first hour" start and end?

Say that out of the oven time is 0:00. Clock begins to run. 60 minutes pass = one hour.

Now we are at 1:00. Think of a round clock face, put one tick mark at 0:00, and another at 1:00.

At the end of that one hour, we are "at" the tick mark that signals the end of the first hour; at 1:00 we are, time wise, at "after the first hour. . ." and "the price decrease[s] by 20%."

The confusion comes from "each" at the beginning of the sentence.

"Each hour after the first hour" seems to suggest that the first hour is not in the group of hours where a decrease happens. The first hour IS in that group.

If I were editing for clarity, I would rewrite: "For every hour after the pastry is taken fresh from the oven, the price decreased by 20 percent."

That said, although I dislike the phrase thoroughly, its obscure quality nonetheless has a meaning that is defensible. Barely, but defensible. :-D

If the answer choices had contained 36 percent, I'd argue otherwise.

Does that help? If not, keep asking about what you don't understand.:-)
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that within me there lay an invincible summer.

-- Albert Camus, "Return to Tipasa"

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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 02 Aug 2017, 11:31
genxer123

Thanks for the clarification.However, if the question is kept as it is and 36 is one of the options the answer would have been 36.right?
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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 02 Aug 2017, 13:31
1
DH99 wrote:
genxer123

Thanks for the clarification.However, if the question is kept as it is and 36 is one of the options the answer would have been 36.right?

I am not sure. I cannot give you a definitive answer. I can say that I have not seen an official question as convoluted as this one and others from non-official sources.

There is no way to be definitive when ambiguity exists; if the question were not worded differently and both answer choices were options (a situation I doubt would exist on real GMAT), I would choose the interpretation that makes a person think harder, or that is less obvious. (In SC, do not do that. Test writers want zero ambiguity in sentences in SC.)

So if 36 percent were an answer choice? Neither 36 percent nor 48.8 percent is definitively correct.

I would choose the latter based on Quant section's alleged inclination to test critical thinking as opposed to computational ability. I haven't checked to see how good this source is, but here is an interesting article on Quant and test writers' penchant for "tricks": https://www.topmba.com/blog/gmat-tips-quant-problem-solving Sorry I can't give you a more definitive answer. :|
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Re: The price of a pastry when made fresh was $P.Each hour after the first  [#permalink]

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New post 17 Apr 2018, 06:06
DHAR wrote:
The price of a pastry when made fresh was $P.Each hour after the first hour the price decreased by 20%.If Lampard bought the pastry when it was just made whereas his sister bought the pastry after 3 hours, then the price paid by Lampard’s sister was what percent less than that paid by Lampard?

A. 33.33%
B. 40%
C. 44%
D. 48.8%
E. 51.2 %


I think OA should be changed. Answer seems to be D.
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Re: The price of a pastry when made fresh was $P.Each hour after the first &nbs [#permalink] 17 Apr 2018, 06:06
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