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Re: If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can d [#permalink]
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Bunuel wrote:
If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if Sam, Lisa, and Tom worked together to complete it?

A. 0.8 days
B. 1.09 days
C. 1.23 days
D. 1.65 days
E. 1.97 days



Given: Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days.

Asked: How long would the job take if Sam, Lisa, and Tom worked together to complete it?

Sam can do 1/4 work in a day
Lisa can do 1/6 work in a day
Tom can do 1/2 work in a day

Sam, Lisa & Tom can do 1/4+1/6+1/2 =11/12 work in a day
How long would the job take if Sam, Lisa, and Tom worked together to complete it = 12/11 = 1.09 days

IMO B
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Re: If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can d [#permalink]
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let the work be 12 unit,
Sam does it in 4 days , so 3 unit per day
similarly, Lisa 2 unit, and Tom 6 unit
if all three work together, its 11 unit in a day
and 12/11 days to complete the work , so 1.09

B is the answer
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Re: If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can d [#permalink]
Bunuel wrote:
If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if Sam, Lisa, and Tom worked together to complete it?

A. 0.8 days
B. 1.09 days
C. 1.23 days
D. 1.65 days
E. 1.97 days
Let, the total work be 12 units...

Efficiency of Sam = 3 units/Day ; Efficiency of Lisa = 2 units/Day & Efficiency of Tom = 6 units/Day

Thus, combined efficiency of Sam, Lisa, and Tom is 11 units/day

Time required to complete 12 units will be 12/11 = 1.xx (Little more than 1), thus Answer must be (B)
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Re: If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can d [#permalink]
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Re: If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can d [#permalink]
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