GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 20 Jun 2018, 21:52

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

Sal and Pat can finish a job together in 3 hours. If Sal can do the jo

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

Hide Tags

Manager
Manager
avatar
Joined: 21 May 2011
Posts: 224
Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 08 Jul 2011, 19:40
5
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

72% (01:20) correct 28% (01:32) wrong based on 428 sessions

HideShow timer Statistics

Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?

A. 20%
B. 30%
C. 40%
D. 50%
E. 60%
2 KUDOS received
Retired Moderator
avatar
B
Joined: 16 Nov 2010
Posts: 1472
Location: United States (IN)
Concentration: Strategy, Technology
Premium Member Reviews Badge
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 08 Jul 2011, 20:34
2
Pat can do the Job alone in 1/(1/3 - 1/5) = 1/2/15 hrs = 7.5 hrs

So in 3 hrs, Pat does 3/7.5 * 100 % = 1000/25 = 40%

Answer - C
_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Senior Manager
Senior Manager
avatar
Joined: 15 May 2011
Posts: 255
Location: Costa Rica
Concentration: Healthcare, International Business
GMAT 1: 710 Q42 V45
GMAT 2: 740 Q48 V42
GPA: 3.3
WE: Research (Consulting)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 10 Jul 2011, 22:53
weird, i was getting D (50%)
Subbed in 30 for work done then backsolved and got the same time for Y, therefore 50%.
I didn't understand your method subhashgosh, could you pls explains how you got the first equation.

Thanks!
_________________


How to improve your RC score, pls Kudo if helpful! http://gmatclub.com/forum/how-to-improve-my-rc-accuracy-117195.html
Work experience (as of June 2012)
2.5 yrs (Currently employed) - Mckinsey & Co. (US Healthcare Analyst)
2 yrs - Advertising industry (client servicing)

1 KUDOS received
Manager
Manager
avatar
Joined: 01 Jun 2011
Posts: 130
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 11 Jul 2011, 01:44
1
subhashghosh wrote:
Pat can do the Job alone in 1/(1/3 - 1/5) = 1/2/15 hrs = 7.5 hrs

So in 3 hrs, Pat does 3/7.5 * 100 % = 1000/25 = 40%

Answer - C



A bit different. I used formula 1/t1+1/t2=1/T

Thus => 1/5 + 1/x (Pet) = 1/3 => 1/5 + 2/15(Pet)= 1/3
=> 2/15 div 1/3 = 40%
Senior Manager
Senior Manager
avatar
Joined: 15 May 2011
Posts: 255
Location: Costa Rica
Concentration: Healthcare, International Business
GMAT 1: 710 Q42 V45
GMAT 2: 740 Q48 V42
GPA: 3.3
WE: Research (Consulting)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 11 Jul 2011, 03:58
Ok, that makes sense too. Thanks Izvos!
_________________


How to improve your RC score, pls Kudo if helpful! http://gmatclub.com/forum/how-to-improve-my-rc-accuracy-117195.html
Work experience (as of June 2012)
2.5 yrs (Currently employed) - Mckinsey & Co. (US Healthcare Analyst)
2 yrs - Advertising industry (client servicing)

5 KUDOS received
Current Student
avatar
Joined: 08 Jan 2009
Posts: 309
GMAT 1: 770 Q50 V46
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 11 Jul 2011, 04:37
5
Sal: 1/5 in 1 hour
Sal: 3/5 in 3 hours

Therefore, pat has done 2/5 = 40% of the job.

Posted from my mobile device
Expert Post
7 KUDOS received
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8102
Location: Pune, India
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 11 Jul 2011, 04:49
7
5
bschool83 wrote:
Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?

A. 20%
B. 30%
C. 40%
D. 50%
E. 60%


You can also use ratios to get the answer in under 10 secs.

Time taken together : Time taken by Sal = 3:5
Rate of work together : Rate of work of Sal = 5:3
So out of 5, Sal does 3 parts of the job and Pat does 2 parts.
2/5 is 40%.

For more on ratios:
http://www.veritasprep.com/blog/2011/03 ... of-ratios/
http://www.veritasprep.com/blog/2011/03 ... os-in-tsd/
http://www.veritasprep.com/blog/2011/03 ... -problems/
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Manager
Manager
avatar
Joined: 01 Jun 2011
Posts: 130
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 11 Jul 2011, 04:57
Pike and veritias. Liked your approach. Saves a lot of time!!!
Senior Manager
Senior Manager
avatar
Joined: 15 May 2011
Posts: 255
Location: Costa Rica
Concentration: Healthcare, International Business
GMAT 1: 710 Q42 V45
GMAT 2: 740 Q48 V42
GPA: 3.3
WE: Research (Consulting)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 28 Jul 2011, 22:43
Could one of you help me solve this question, based on both Carishma's ratio method and the regular "inverse of time to get the rate" method? I got the answer, but intuitively, and was unable to set up the final equation to determine % contribution to work:

Working alone at its own constant rate, a machine seals k cartons in 8 hours, and working alone at its own constant rate, a 2nd machine seals k cartons in 4 hours. If the two machines, each working at its own constant rate and for the same period of time, together sealed a certain number of cartons, what % of the cartons were sealed by the machine working at the faster rate?
a) 25% b) 33 1/3% c) 50% d) 66 2/3% e) 75%


Scroll down for the answer
_________________


How to improve your RC score, pls Kudo if helpful! http://gmatclub.com/forum/how-to-improve-my-rc-accuracy-117195.html
Work experience (as of June 2012)
2.5 yrs (Currently employed) - Mckinsey & Co. (US Healthcare Analyst)
2 yrs - Advertising industry (client servicing)

Senior Manager
Senior Manager
avatar
Joined: 15 May 2011
Posts: 255
Location: Costa Rica
Concentration: Healthcare, International Business
GMAT 1: 710 Q42 V45
GMAT 2: 740 Q48 V42
GPA: 3.3
WE: Research (Consulting)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 28 Jul 2011, 23:47
ok worked on it a bit more, if you take the rate of the 2nd machine and divide it by the calculated combined rate, it gives you the % contribution to overall work by that machine:
k/4
3k/8
=2/3 (or 66.66%) or D
_________________


How to improve your RC score, pls Kudo if helpful! http://gmatclub.com/forum/how-to-improve-my-rc-accuracy-117195.html
Work experience (as of June 2012)
2.5 yrs (Currently employed) - Mckinsey & Co. (US Healthcare Analyst)
2 yrs - Advertising industry (client servicing)

1 KUDOS received
Manager
Manager
User avatar
Status: mba here i come!
Joined: 07 Aug 2011
Posts: 237
GMAT ToolKit User
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 21 Aug 2011, 12:05
1
1
pal would take = 3*5/2 = 15/2 hrs to complete the job
OR pal in 1hr can do 2/15 of the job
in 3 hr pal will do 6/15 = 2/5 of the job

2/5 of the job OR 40%
_________________

press +1 Kudos to appreciate posts
Download Valuable Collection of Percentage Questions (PS/DS)

Director
Director
avatar
Joined: 01 Feb 2011
Posts: 686
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 21 Aug 2011, 19:28
1/5 + 1/p = 1/3 => p = 15/2

=> pat can do the work 1 alone in 15/2 hours = > pats rate = 2/15

amount of work done by pat in 3 hours = (2/15)*3 = 2/5

i.e ((2/5)/1)*100 = 40%
Manager
Manager
User avatar
B
Joined: 20 Jan 2017
Posts: 61
Location: United States (NY)
Schools: CBS '20 (A)
GMAT 1: 750 Q48 V44
GMAT 2: 610 Q34 V41
GPA: 3.92
Reviews Badge
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 02 Feb 2017, 04:08
1) First we need to find Sal's and Pat's rates:
Rate of Sal and Pat working together: \(\frac{1}{3}\)
Rate of Sal: \(\frac{1}{5}\)
Rate of Pat: \(\frac{1}{3}\)-\(\frac{1}{5}=\frac{2}{15}\)
2) Now we can compare rate's of Sal and Pat: \(\frac{1}{5} vs. \frac{2}{15}; \frac{3}{15} vs. \frac{2}{15}\) While Pat does 2 segments of work, Sal does 3. This means that when the job id done, Pat has completed 40% of work.

The correct answer is C.
Board of Directors
User avatar
G
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3511
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 02 Feb 2017, 11:39
bschool83 wrote:
Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?

A. 20%
B. 30%
C. 40%
D. 50%
E. 60%


Let the total work be 15 units

(S + P )'s efficiency / hr is 5 units/hr
S's efficiency / hr is 3 units/hr

So, P's efficiency / hr is 2 units/hr

So, P does 2/5*100 => 40% job....

Answer will be (C) 40%
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

VP
VP
avatar
G
Joined: 07 Dec 2014
Posts: 1018
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 02 Feb 2017, 12:42
bschool83 wrote:
Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?

A. 20%
B. 30%
C. 40%
D. 50%
E. 60%


Sal's percent of job=(1/5)/(1/3)=3/5=60%
Pat's percent of job=100-60=40%
Intern
Intern
avatar
Joined: 12 Mar 2016
Posts: 9
GMAT ToolKit User
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 05 Feb 2017, 19:35
Rate of Sal & Pat together = 1\3
Rate of Sal = 1\5
Rate of Pat = 1\3 - 1\5 = 2\15
Total work done by Pat = 2\15 * 3 = 2\5 = 40%
Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2758
Location: United States (CA)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 08 Feb 2017, 11:21
bschool83 wrote:
Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?

A. 20%
B. 30%
C. 40%
D. 50%
E. 60%


We are given that Sal and Pat, working together, can complete a job in 3 hours. Since rate = work/time, the combined rate of Sal and Pat is 1/3. We are also given that Sal can complete the job alone is 5 hours; thus he has a rate of 1/5.

Since Sal’s rate + Pat’s rate = the combined rate, Pat’s rate = the combined rate - Sal’s rate. That is, Pat’s rate = 1/3 - 1/5 = 5/15 - 3/15 = 2/15.

Thus, when the job is completed, Pat completes (2/15)(3) = 6/15 = 2/5 = 0.4 = 40% of the job.

Answer: C
_________________

Scott Woodbury-Stewart
Founder and CEO

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

Intern
Intern
avatar
B
Joined: 19 Aug 2016
Posts: 4
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]

Show Tags

New post 26 Mar 2017, 13:04
1) Assume total work = 30 (e.g., cars)

2) Sal:
Work=30 cars
Time alone=5 hours
Speed=30/5=6 cars/hour
Work done in 3 hours (that he works together with Pat)=6*3=18 cars (out of 30 cars)=60%

3) Pat
Work done in 3 hours (that he works together with Sal)=100%-60%=40% (C)
Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo   [#permalink] 26 Mar 2017, 13:04
Display posts from previous: Sort by

Sal and Pat can finish a job together in 3 hours. If Sal can do the jo

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


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.