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

 It is currently 25 May 2013, 21:32

# Ram can do a piece of work in 8 days which syam can finsih

Author Message
TAGS:
Intern
Joined: 03 Jan 2006
Posts: 28
Followers: 0

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

Ram can do a piece of work in 8 days which syam can finsih [#permalink]  05 Feb 2007, 11:34
Ram can do a piece of work in 8 days which syam can finsih in 12 days.If they work at it on alternate days,with Ram begining,in how many days,the work will be finished?
Senior Manager
Joined: 04 Jan 2006
Posts: 282
Followers: 1

Kudos [?]: 14 [0], given: 0

Re: Ram and Shyam [#permalink]  05 Feb 2007, 13:59
sravan_m444 wrote:
Ram can do a piece of work in 8 days which syam can finsih in 12 days.If they work at it on alternate days,with Ram begining,in how many days,the work will be finished?

Ram's Work Rate = R = 1/8 (work/day)
Syam's Work Rate = S = 1/12 (work/day)

Before the job is done, if Ram work n days, Syam will also works n days.
Therefore, work done by Ram = n/8 work
work done by Syam = n/12

As mentioned above that both work is not done, we can write this statement
n/8 + n/12 <= 1
n* ((3+2)/24) <= 1
n <= 24/5
n <= 4.8 days
This means that Ram and Syam will have to work at least 4 days each before the job can be done.
Work from Ram = 4 * 1/8 = 1/2
Work from Syam = 4 * 1/12 = 1/3
Total = 1/2 + 1/3 = 5/6
On 8th day, the job remain 1 - 5/6 = 1/6 work
On 9th day, Ram will work on this day and the job remain = 1/6 - 1/8 = 1/24.
On the 10th day, Syam will do the rest and the job is done.

Therefore, it will take 10 days to finish the job.
Senior Manager
Joined: 04 Jan 2006
Posts: 282
Followers: 1

Kudos [?]: 14 [0], given: 0

Here is another approach for this question.

R = 1/8 (work/day)
S = 1/12 (work/day)

If they work together, their work rate = (1/8 + 1/12) = 5/24 (work/day)

They will need 24/5 (day/work) = 4.8 days to finish one work.

But since Ram and Syam will work on alternate day they will need total of 4.8 x 2 = 9.6 days = 10 days to finish the work.
Director
Joined: 12 Jun 2006
Posts: 544
Followers: 1

Kudos [?]: 6 [0], given: 1

Quote:
Ram can do a piece of work in 8 days which syam can finsih in 12 days.If they work at it on alternate days,with Ram begining,in how many days,the work will be finished?
Ram
rt = w
r(8) = 1
r= 1/8

Syam
rt = w
r(12) = 1
r=1/2

1/8 + 1/12 = 5/24

5/24(x) = 1
****remember, 5/24 is really 1/8 + 1/12, in other words, 2 days****
x = 4.8
4.8*2 = 9.6 = 10 days
Manager
Joined: 10 Dec 2005
Posts: 114
Followers: 1

Kudos [?]: 2 [0], given: 0

R can do 1/8 of the job in 1 day
S can do 1/12 off the job in 1 day

If R and S both worked together for a day they can finish (1/8 + 1/12) of the job

meaning 5/24 of the job can be done in 1 day
Therefore to do 1 jobit will take 24/5 days = 4.8 days

Since both are working alternate days it will take twice as long, meaning 2(4.8) days = 9.6 = 10 days.
_________________

"Live as if you were to die tomorrow. Learn as if you were to live forever." - Mahatma Gandhi

Manager
Joined: 12 Feb 2006
Posts: 119
Followers: 1

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

We know that it will take more than 8 days because that is how long R alone can do the job. So R 5d ays and S 4 days = 5/8 + 1/3 = 23/24.

Therefore we need one more day or 10.

This isn't has fast as the other guys, but if you are math moron like me it gets the job done.
Similar topics Replies Last post
Similar
Topics:
If 12 men and 16 women can do a piece of work in 5 days and 4 17 Aug 2004, 15:19
A and B together can do a piece of work in 72/5 days ; B and 1 08 Oct 2006, 04:37
A and B together can do a peace of work in 12 days,which B 13 05 Feb 2007, 11:30
2 Matt and Peter can do together a piece of work in 20 days 12 11 Mar 2008, 03:56
2 Micheal and Adam can do together a piece of work in 20 days. 3 11 Mar 2008, 04:47
Display posts from previous: Sort by