Last visit was: 17 May 2024, 19:45 It is currently 17 May 2024, 19:45
Toolkit
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

# The price of a pastry at 10AM was $p. Each hour after 11AM, the price SORT BY: Tags: Show Tags Hide Tags Read Only User Joined: 25 Dec 2018 Posts: 116 Own Kudos [?]: 404 [16] Given Kudos: 146 Location: India GMAT 1: 490 Q47 V13 GPA: 2.86 Director Joined: 27 Oct 2018 Status:Manager Posts: 683 Own Kudos [?]: 1871 [5] Given Kudos: 200 Location: Egypt Concentration: Strategy, International Business GPA: 3.67 WE:Pharmaceuticals (Health Care) VP Joined: 28 Jul 2016 Posts: 1210 Own Kudos [?]: 1735 [2] Given Kudos: 67 Location: India Concentration: Finance, Human Resources Schools: ISB '18 (D) GPA: 3.97 WE:Project Management (Investment Banking) Intern Joined: 01 Jun 2017 Posts: 2 Own Kudos [?]: 8 [2] Given Kudos: 105 Location: United States (VA) Concentration: General Management, Finance GPA: 3.4 WE:Engineering (Telecommunications) Re: The price of a pastry at 10AM was$p. Each hour after 11AM, the price [#permalink]
1
Kudos
1
Bookmarks
can be done by assuming the initial price i.e. price of the pastry 10 AM - > 10

10 AM - > $10 (price paid by Julie) 11 - >$10 *.8 -> $8 (price paid by Julie) 12 - >$8 * .8 - > $6.4 1 ->$6.4 * .8 -> $5.12 @ 2 ->$5.12*.8 -> 4.096

price paid of Julie's sis - > 4.096

% difference= > (4.096/8) -> here numerator is greater than 50% of 8, thus the %value will be slightly lower than 50%.

from the given choices - > only C works out as an option. thus ANS - > C
Tutor
Joined: 16 Oct 2010
Posts: 14891
Own Kudos [?]: 65335 [0]
Given Kudos: 431
Location: Pune, India
Re: The price of a pastry at 10AM was $p. Each hour after 11AM, the price [#permalink] Expert Reply akurathi12 wrote: The price of a pastry at 10 AM was$p. Each hour after 11 AM, the price decreases by 20%. If Julie bought the pastry at 11:15 AM whereas her sister bought the same 3 hours later, then the price paid by Julie's sister was what percent less than that paid by Julie?(There is no price change apart from those mentioned above)

A. 33.33%
B. 37.5%
C. 48.8%
D. 51.2%
E. None of these

There is a reduction of 20% every hour so the price becomes (4/5) of what it was in the previous hour.

At 11:15, Julie bought the pastry for p*(4/5)
3 hrs later, at 2:15, her sister bought the pastry for p*(4/5)*(4/5)^3 = p*(4/5)^4 = p*(256/625)

% Diff = [p*(4/5) - p*(256/625)] / p*(4/5) = 1 - (256 * 5)/(625 * 4) = 61/125 = 48.8% ( because 61 is a bit less than 62.5 which is half of 125)

Manager
Joined: 07 Oct 2022
Posts: 93
Own Kudos [?]: 19 [1]
Given Kudos: 45
Location: Nigeria
Re: The price of a pastry at 10AM was $p. Each hour after 11AM, the price [#permalink] 1 Bookmarks Julie will by it at$p. Her sister will buy it at

0.8x0.8x0.8p = 0.512p.

Percentage decrease =

p-0.512p

= 0.488p

0.488p/p x 100 = 48.8%

Posted from my mobile device
Intern
Joined: 28 Jul 2022
Posts: 36
Own Kudos [?]: 40 [0]
Given Kudos: 100
Re: The price of a pastry at 10AM was $p. Each hour after 11AM, the price [#permalink] akurathi12 wrote: The price of a pastry at 10 AM was$p. Each hour after 11 AM, the price decreases by 20%. If Julie bought the pastry at 11:15 AM whereas her sister bought the same 3 hours later, then the price paid by Julie's sister was what percent less than that paid by Julie?(There is no price change apart from those mentioned above)

A. 33.33%
B. 37.5%
C. 48.8%
D. 51.2%
E. None of these

­KarishmaB Ma'am have a very basic doubt, How to read "then the price paid by Julie's sister was what percent less than that paid by Julie?" is it same as "price paid by Julie's sister was what percent than that paid by Julie?"?
Intern
Joined: 20 Jul 2020
Posts: 28
Own Kudos [?]: 4 [0]
Given Kudos: 58
Re: The price of a pastry at 10AM was $p. Each hour after 11AM, the price [#permalink] Let p$ be 100$Julie bought the pastry at 100$
Julie's sister bought the pastry at 100$-20% =80$
80$- 20% = 64$
64$- 20% = 51.2$

Julie's sister paid = 48.8% less

((51.2$-100)/100*100)= 48.8% Re: The price of a pastry at 10AM was$p. Each hour after 11AM, the price [#permalink]
Moderators:
Math Expert
93334 posts
Senior Moderator - Masters Forum
3137 posts