No-Drip Painting

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No-Drip Painting

by sivaelectric » Mon Jun 06, 2011 3:23 am
No-drip painting has three four-man work crews, A, B and C, assigned to paint the identical houses of the Merry Meadows development. Crew A, working alone, can completely paint a house in eight hours. Crews B and C, working alone, could each paint a house in six hours. If the supervisor assigns all three crews to work together on a single house one day, how long will it take them to completely paint the house if they all work at their independent constant rates?

A. 24/11 hours
B. 36/11 hours
C. 7 hours
D. 96/11 hours
E. 96/7 hours
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by GMATGuruNY » Mon Jun 06, 2011 4:03 am
sivaelectric wrote:No-drip painting has three four-man work crews, A, B and C, assigned to paint the identical houses of the Merry Meadows development. Crew A, working alone, can completely paint a house in eight hours. Crews B and C, working alone, could each paint a house in six hours. If the supervisor assigns all three crews to work together on a single house one day, how long will it take them to completely paint the house if they all work at their independent constant rates?

A. 24/11 hours
B. 36/11 hours
C. 7 hours
D. 96/11 hours
E. 96/7 hours
Let job = 24 units.
Rate for Crew A = w/t = 24/8 = 3 units per hour.
Rate for Crew B alone and for Crew C alone = w/t = 24/6 = 4 units per hour.
Combined rate for A, B and C working together = 3+4+4 = 11 units per hour.
Time for A, B and C together = w/r = 24/11 hours.

The correct answer is A.
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by Anurag@Gurome » Mon Jun 06, 2011 4:04 am
sivaelectric wrote:No-drip painting has three four-man work crews, A, B and C, assigned to paint the identical houses of the Merry Meadows development. Crew A, working alone, can completely paint a house in eight hours. Crews B and C, working alone, could each paint a house in six hours. If the supervisor assigns all three crews to work together on a single house one day, how long will it take them to completely paint the house if they all work at their independent constant rates?

A. 24/11 hours
B. 36/11 hours
C. 7 hours
D. 96/11 hours
E. 96/7 hours
A's 1 day work = 1/8
B's 1 day work = 1/6
C's 1 day work = 1/6
(A + B + C)'s 1 day work = 1/8 + 1/6 + 1/6 = 11/24

Therefore, it takes [spoiler]24/11[/spoiler] hrs to completely paint the house if they all work at their independent constant rates.

The correct answer is A.
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by Shankenstein » Mon Jun 06, 2011 4:10 am
Let's assume that to complete a house a team or a group teams needs to 48 units of work.
If A does a house in 8 days it'll do 6 units in a day. similarly B and C do 8 units each.
so time for A,B and C together is - 48/22=24/11.

So answer is A. :D

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by cans » Mon Jun 06, 2011 7:15 am
No-drip painting has three four-man work crews, A, B and C, assigned to paint the identical houses of the Merry Meadows development. Crew A, working alone, can completely paint a house in eight hours. Crews B and C, working alone, could each paint a house in six hours. If the supervisor assigns all three crews to work together on a single house one day, how long will it take them to completely paint the house if they all work at their independent constant rates?
A-8 hours;B-6 hours;C-6 hours
let work=24
rate A=3,B=4,C=4
Total=3+4+4=11
work=24
time=24/11
IMO A
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by sivaelectric » Mon Jun 06, 2011 7:57 am
OA A
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