Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 Jun 2015, 10:05

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Four carpenters can individually complete a particular task

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Intern
Joined: 26 May 2012
Posts: 10
Concentration: Human Resources, Leadership
GMAT Date: 07-04-2012
Followers: 0

Kudos [?]: 1 [0], given: 8

Four carpenters can individually complete a particular task [#permalink]  05 Jun 2012, 09:02
00:00

Difficulty:

15% (low)

Question Stats:

80% (02:47) correct 20% (02:21) wrong based on 163 sessions
Four carpenters can individually complete a particular task in 3, 4, 5, and 7 hours, respectively. What is the maximum fraction of the task that can be completed in forty-five minutes if three of the carpenters work together at their respective rates ?

A. 11/15
B. 3/5
C. 11/30
D. 47/80
E. 5/9
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 27598
Followers: 4344

Kudos [?]: 42890 [0], given: 6126

Re: Four carpenters can individually complete a particular task [#permalink]  05 Jun 2012, 09:21
Expert's post
Four carpenters can individually complete a particular task in 3, 4, 5, and 7 hours, respectively. What is the maximum fraction of the task that can be completed in forty-five minutes if three of the carpenters work together at their respective rates ?

A. 11/15
B. 3/5
C. 11/30
D. 47/80
E. 5/9

In order three of the carpenters to complete the maximum fraction of the task we should select three fastest carpenters. So, those three who complete the task in 3, 4, and 5 hours.

In 1 hour they will complete $$\frac{1}{3}+\frac{1}{4}+\frac{1}{5}=\frac{47}{60}$$th of the task. So, in $$\frac{3}{4}$$ hour (45 minutes) they will complete $$\frac{47}{60}*\frac{3}{4}=\frac{47}{80}$$th of the job.

Hope it's clear.
_________________
Current Student
Joined: 08 Jan 2009
Posts: 328
GMAT 1: 770 Q50 V46
Followers: 23

Kudos [?]: 105 [0], given: 7

Re: Four carpenters can individually complete a particular task [#permalink]  05 Jun 2012, 14:33
1/3 + 1/4 + 1/5 = 47/60
47/60 * 3/4 = 47 / 80

D
Manager
Status: Rising GMAT Star
Joined: 05 Jun 2012
Posts: 133
Location: Philippines
Concentration: General Management, Finance
GMAT 1: 660 Q V
GPA: 3.22
WE: Corporate Finance (Consulting)
Followers: 6

Kudos [?]: 24 [0], given: 16

Re: Four carpenters can individually complete a particular task [#permalink]  05 Jun 2012, 17:05
Four carpenters can individually complete a particular task in 3, 4, 5, and 7 hours, respectively. What is the maximum fraction of the task that can be completed in forty-five minutes if three of the carpenters work together at their respective rates ?

A. 11/15
B. 3/5
C. 11/30
D. 47/80
E. 5/9

Farmer A, B, C, and D

A's rate: 1/3 job/hour
B's rate: 1/4 job/hour
C's rate: 1/5 job/hour
D's rate: 1/7 job/hour

By intuition we know that the three fastest farmers are A B and C.

As such

(1/3 + 1/4 + 1/5)*(3/4) = ?

47/80 or (D)
_________________

Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure... than to rank with those poor spirits who neither enjoy nor suffer much, because they live in a gray twilight that knows not victory nor defeat.
- T. Roosevelt

Math Expert
Joined: 02 Sep 2009
Posts: 27598
Followers: 4344

Kudos [?]: 42890 [0], given: 6126

Re: Four carpenters can individually complete a particular task [#permalink]  14 Jun 2013, 04:27
Expert's post
Bumping for review and further discussion*. Get a kudos point for an alternative solution!

*New project from GMAT Club!!! Check HERE

All DS Min/Max Problems to practice: search.php?search_id=tag&tag_id=42
All PS Min/Max Problems to practice: search.php?search_id=tag&tag_id=63

_________________
Re: Four carpenters can individually complete a particular task   [#permalink] 14 Jun 2013, 04:27
Similar topics Replies Last post
Similar
Topics:
6 Each of the three people individually can complete a certain job in 3, 8 12 Jan 2015, 10:03
2 If ‘A’ can complete a task in 3 hours and ‘B’ can complete 12 08 Mar 2010, 02:00
Al can complete a particular job in 8 hours. Boris can 0 30 Oct 2014, 00:16
13 John can complete a given task in 20 days. Jane will take 7 20 Jul 2008, 04:23
14 Al can complete a particular job in 8 hours. Boris can 12 11 Jul 2006, 20:20
Display posts from previous: Sort by

Four carpenters can individually complete a particular task

 Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO 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®.