• NEW! FREE Beat The GMAT Quizzes
Hundreds of Questions Highly Detailed Reporting Expert Explanations
• 7 CATs FREE!
If you earn 100 Forum Points

Engage in the Beat The GMAT forums to earn
100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## Last year, the price of a jar of peanut butter at a certain tagged by: AAPL ##### This topic has 2 expert replies and 1 member reply ### Top Member ## Last year, the price of a jar of peanut butter at a certain ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult Veritas Prep Last year, the price of a jar of peanut butter at a certain store was $$P$$ dollars and the price of a jar of jelly at the same store was $$J$$ dollars, where $$J=2P$$. This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20%. If a customer purchases one jar of peanut butter and one jar of jelly this year and receives a 25% discount, which of the following represents the amount that he paid, in terms of $$P$$? A. $$3\frac{P}{2}$$ B. $$17\frac{P}{10}$$ C. $$19\frac{P}{10}$$ D. $$21\frac{P}{10}$$ E. $$11\frac{P}{5}$$ OA D ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15383 messages Followed by: 1872 members Upvotes: 13060 GMAT Score: 790 AAPL wrote: Veritas Prep Last year, the price of a jar of peanut butter at a certain store was $$P$$ dollars and the price of a jar of jelly at the same store was $$J$$ dollars, where $$J=2P$$. This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20%. If a customer purchases one jar of peanut butter and one jar of jelly this year and receives a 25% discount, which of the following represents the amount that he paid, in terms of $$P$$? A. $$3\frac{P}{2}$$ B. $$17\frac{P}{10}$$ C. $$19\frac{P}{10}$$ D. $$21\frac{P}{10}$$ E. $$11\frac{P}{5}$$ The price of a jar of peanut butter at a certain store was P dollars and the price of a jar of jelly at the same store was J dollars, where J=2P. Let P = 10 and J = 20 This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20% New P = 10 + (20% of 10) = 10 + 2 = 12 New J = 20 - (20% of 20) = 20 - 4 = 16 A customer purchases one jar of peanut butter and one jar of jelly this year and receives a 25% discount. Before the discount: New P + New J = 12 + 16 = 28 After the discount: 28 - (25% of 28) = 28 - 7 = 21 Which of the following represents the amount that he paid, in terms of P? The correct answer must yield$21 when P=10.
Only D works:
21P/10 = (21*10)/10 = 21.

_________________
Mitch Hunt
Private Tutor for the GMAT and GRE
GMATGuruNY@gmail.com

If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.

Available for tutoring in NYC and long-distance.
Student Review #1
Student Review #2
Student Review #3

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

### Top Member

Legendary Member
Joined
29 Oct 2017
Posted:
1007 messages
Followed by:
4 members
Let $$P=100$$, thus $$J=200$$, last year.

So this year $$P = 120$$ (20% increase), and $$J = 160$$ (20% decrease). Price paid this year by customer $$= 120+160 = 280$$.

But after 25% discount, price $$=$$ 75% of 280 $$= \frac{3}{4} \cdot 280 = 210$$.

So we have to look for an option where if we put $$P=100$$, we should get an answer as '210'.

Hence, __D__ is the correct answer.

### GMAT/MBA Expert

GMAT Instructor
Joined
09 Apr 2015
Posted:
1465 messages
Followed by:
19 members
39
AAPL wrote:
Veritas Prep

Last year, the price of a jar of peanut butter at a certain store was $$P$$ dollars and the price of a jar of jelly at the same store was $$J$$ dollars, where $$J=2P$$. This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20%. If a customer purchases one jar of peanut butter and one jar of jelly this year and receives a 25% discount, which of the following represents the amount that he paid, in terms of $$P$$?

A. $$3\frac{P}{2}$$

B. $$17\frac{P}{10}$$

C. $$19\frac{P}{10}$$

D. $$21\frac{P}{10}$$

E. $$11\frac{P}{5}$$

OA D
We are given that last year, the price of a jar of peanut butter at a certain store was P dollars, and the price of a jar of jelly at the same store was J dollars, where J = 2P.

This year the peanut butter price increased by 20%, so the new price is 1.2P.

Since the price of jelly decreased by 20%, the new price is 0.8J = 0.8(2P) = 1.6P.

Thus, the regular price of one jar of peanut butter and one jar of jelly is 1.2P + 1.6P = 2.8P.

Thus, at a 25% discount, the price is 0.75(2.8P) = 2.1P = 21P/10

_________________

Jeffrey Miller
jeff@targettestprep.com

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to $200 Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • FREE GMAT Exam Know how you'd score today for$0

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

### Top First Responders*

1 Ian Stewart 41 first replies
2 Brent@GMATPrepNow 40 first replies
3 Scott@TargetTestPrep 39 first replies
4 Jay@ManhattanReview 32 first replies
5 GMATGuruNY 26 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

### Most Active Experts

1 Scott@TargetTestPrep

Target Test Prep

159 posts
2 Max@Math Revolution

Math Revolution

92 posts
3 Brent@GMATPrepNow

GMAT Prep Now Teacher

60 posts
4 Ian Stewart

GMATiX Teacher

50 posts
5 GMATGuruNY

The Princeton Review Teacher

37 posts
See More Top Beat The GMAT Experts