A 2 Part question on Time and Work

This topic has expert replies

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 645
Joined: 26 Jul 2010
Location: US
Thanked: 527 times
Followed by:227 members

A 2 Part question on Time and Work

by e-GMAT » Tue Jan 01, 2013 9:29 pm
Hello Friends,

Please try this 2 part question.

A, B, & C can do the same job in 8, 24, & 48 hours respectively working individually. It was decided that each of them will work on this job alternatively for an hour. They can start the work in any order. Select 'Minimum hours', & 'Maximum hours' required to complete the job in the table. Make only two selections, one in each column.

-Shalabh
Attachments
Options.JPG

User avatar
MBA Admissions Consultant
Posts: 2278
Joined: 11 Nov 2011
Location: New York
Thanked: 660 times
Followed by:266 members
GMAT Score:770

by [email protected] » Fri Jan 04, 2013 2:53 pm
Nice question... Just a hint for those trying:

1/8 + 1/24 + 1/48 + 1/8 + 1/24 ...... keep up this sequence to find the fastest.
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image

User avatar
MBA Admissions Consultant
Posts: 2278
Joined: 11 Nov 2011
Location: New York
Thanked: 660 times
Followed by:266 members
GMAT Score:770

by [email protected] » Fri Jan 04, 2013 2:53 pm
The answer is when the sequent equals 1....
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image

Senior | Next Rank: 100 Posts
Posts: 45
Joined: 06 Apr 2012
Thanked: 3 times
Followed by:2 members
GMAT Score:500

by BTG14 » Tue Jan 15, 2013 11:19 pm
Step 1: in three hours : (1/8 + 1/24+ 1/48)=9/48.
Step 2: in (3*5) hours : 9*5/48=45/48. will be completed.

Now to be minimum let 45/48+1/8 which is more than 1. So the answer lies between 15 and 16.

Now to be maximum 45/48+1/48+1/24=1 which is 17 hours.

Answer will be : Minimum:15.5
Maximum 17 hours