It is currently 20 Oct 2017, 20:57

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A certain store sold pens for $0.35 each and pencils for $0.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
Director
Director
User avatar
Status: 1,750 Q's attempted and counting
Affiliations: University of Florida
Joined: 09 Jul 2013
Posts: 514

Kudos [?]: 989 [1], given: 630

Location: United States (FL)
Schools: UFL (A)
GMAT 1: 600 Q45 V29
GMAT 2: 590 Q35 V35
GMAT 3: 570 Q42 V28
GMAT 4: 610 Q44 V30
GPA: 3.45
WE: Accounting (Accounting)
A certain store sold pens for $0.35 each and pencils for $0. [#permalink]

Show Tags

New post 24 Oct 2013, 09:57
1
This post received
KUDOS
8
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

70% (01:30) correct 30% (01:43) wrong based on 183 sessions

HideShow timer Statistics

A certain store sold pens for $0.35 each and pencils for $0.25 each. If a customer purchased both pens and pencils from the store for a total of $2.50, what total number of pens and pencils did the customer purchase?

(A) 8
(B) 9
(C) 10
(D) 11
(E) 12

GH-04.05.13 - OE to follow
[Reveal] Spoiler: OA

Kudos [?]: 989 [1], given: 630

Expert Post
2 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 41892

Kudos [?]: 129048 [2], given: 12187

Re: A certain store sold pens for $0.35 each and pencils for $0. [#permalink]

Show Tags

New post 24 Oct 2013, 10:04
2
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
avohden wrote:
A certain store sold pens for $0.35 each and pencils for $0.25 each. If a customer purchased both pens and pencils from the store for a total of $2.50, what total number of pens and pencils did the customer purchase?

(A) 8
(B) 9
(C) 10
(D) 11
(E) 12

GH-04.05.13 - OE to follow


\(0.35x+25y=2.5\);
\(35x+25y=250\);
\(7x+5y=50\).

Since x and y must be positive integers, then only one solution exists: x=5 and y=3 --> x+y=8.

Answer: A.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 129048 [2], given: 12187

1 KUDOS received
Director
Director
User avatar
Status: 1,750 Q's attempted and counting
Affiliations: University of Florida
Joined: 09 Jul 2013
Posts: 514

Kudos [?]: 989 [1], given: 630

Location: United States (FL)
Schools: UFL (A)
GMAT 1: 600 Q45 V29
GMAT 2: 590 Q35 V35
GMAT 3: 570 Q42 V28
GMAT 4: 610 Q44 V30
GPA: 3.45
WE: Accounting (Accounting)
Re: A certain store sold pens for $0.35 each and pencils for [#permalink]

Show Tags

New post 27 Oct 2013, 10:41
1
This post received
KUDOS
Official Explanation

Answer: A
Algebraically, the question looks like this: 2.5 = 0.35x + 0.25y

However, that's the only equation we get, so we can't solve for x and y this way. There would be an infinite number of possible values of x and y. Instead, we must use an intelligent version of guessing and checking. Since at least one pencil and one pen is purchased, the customer must spend at least $2.25 ($2.50 minus $0.25) on pens. There are six possible numbers of pens that fit that requirement:

1 pen: $0.35
2 pens: $0.70
3 pens: $1.05
4 pens: $1.40
5 pens: $1.75
6 pens: $2.10

Many of those aren't applicable here, though. For instance, if the customer bought 6 pens, he would need to spend an additional $0.40 on pencils. At $0.25 per pencil, that's impossible. Consider each of the other 5:

1 pen: $2.15 on pencils
2 pens: $1.80 on pencils
3 pens: $1.45 on pencils
4 pens: $1.10 on pencils
5 pens: $0.75 on pencils

Only the last of these works. $0.75 is 3 pencils for $0.25 each. That's 5 pens and 3 pencils for a total of 8 pens and pencils. Choice (A) is correct.

Kudos [?]: 989 [1], given: 630

Senior Manager
Senior Manager
avatar
Joined: 02 Dec 2014
Posts: 374

Kudos [?]: 90 [0], given: 349

Location: Russian Federation
Concentration: General Management, Economics
GMAT 1: 640 Q44 V33
WE: Sales (Telecommunications)
Re: A certain store sold pens for $0.35 each and pencils for $0. [#permalink]

Show Tags

New post 10 Mar 2015, 03:16
A certain store sold pens for $0.35 each and pencils for $0.25 each. If a customer purchased both pens and pencils from the store for a total of $2.50, what total number of pens and pencils did the customer purchase?

(A) 8
(B) 9
(C) 10
(D) 11
(E) 12

If you don't want to pick up numbers here is one more solution.
Let x is a number of penc and y is a number of pencils, Then we have that 0.35x+0.25y=2.5 Multiply by 100 both parts to get 35x+25y=250 ==>7x+5y=50. Now let's factor out 5 ==>5((7/5)x+y)=50. Divide by 5 to get (7/5)x+y=10. Now since both x and y are integers it is clear that x is a multiple of 5. So we can pick numbers. Lets start with x=5 ==> y=3 and x+y=8. Looks good but let's try x=10. Now we have y=-4 which is impossible. Hence x=5,y=3 and answer is A. Hope it is clear
_________________

"Are you gangsters?" - "No we are Russians!"

Kudos [?]: 90 [0], given: 349

Expert Post
Target Test Prep Representative
User avatar
S
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 1648

Kudos [?]: 843 [0], given: 3

Location: United States (CA)
Re: A certain store sold pens for $0.35 each and pencils for $0. [#permalink]

Show Tags

New post 09 Oct 2017, 17:54
avohden wrote:
A certain store sold pens for $0.35 each and pencils for $0.25 each. If a customer purchased both pens and pencils from the store for a total of $2.50, what total number of pens and pencils did the customer purchase?

(A) 8
(B) 9
(C) 10
(D) 11
(E) 12


We can let the number of pens = a and the number of pencils = b; thus:

0.35a + 0.25b = 2.50

35a + 25b = 250

7a + 5b = 50

7a = 50 - 5b

7a = 5(10 - b)

a = 5(10 - b)/7

Since a and b are integers, we see that b must be 3. Thus, a = 5(7)/7 = 5.

Thus, the total number of pens and pencils is 3 + 5 = 8.

Answer: A
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Kudos [?]: 843 [0], given: 3

Re: A certain store sold pens for $0.35 each and pencils for $0.   [#permalink] 09 Oct 2017, 17:54
Display posts from previous: Sort by

A certain store sold pens for $0.35 each and pencils for $0.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.