First off, I would like to thank everyone for their help on previous problems I have posted.
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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?
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I need to know the STEPS in solving this. Thank you in advance.
2007-01-23 20:26:55 · 5 answers · asked by bubbie_king 2 in Science & Mathematics ➔ Mathematics
Hint: Amount of work done in 1 day = reciprocal of no. of days taken to finish the work. Sam takes 4 days to do the work, therefore, in 1 day, Sam will finish 1/4 of the work. Similarly, Lisa and Tom will finish 1/6 and 1/2 of the work in one day. If they work together, they will finish 1/4 + 1/6+1/2 =(3+2+6)/12 = 11/12 of the work in 1 day. Then for the entire work to be done, (reversing the hint stated at the beginning) it will take 12/11 day or 1 day 2 hours approx.
2007-01-23 20:38:49 · answer #1 · answered by Kow Yan L 1 · 1⤊ 0⤋
s = 1/4job per day
L = 1/6 jon per day
T = 1/2 job per day
s+l+t = 1/4+1/6+1/2 = 3/12+2/12+6/12 = 11/12
so they can get a job done in 11/12 of a day
SO 1 day + 1/12 of a day
I dont know what they mean by day ... is it a 8 hour work day or 24 hour period
If it is a 24 hr period, than it is 1 + 1/12 days = 24 hrs +1/12*34=24+2 = 26 hours
2007-01-24 04:33:22 · answer #2 · answered by Bill F 6 · 0⤊ 1⤋
Use the units to help guide you to the equation:
Sam’s Rate is: R_Sam = (4days/job)
Lisa’s Rate is: R_Lisa = (6days/job)
Tom’s Rate is: R_Tom = (2days/job)
Alone, it takes Sam (4days/job)(1job) = 4 days
Alone, it takes Lisa (6days/job)(1job) = 6 days
Alone, it takes Tom (2days/job)(1job) = 2 days
So together we want them to complete 1 job in x days:
1 job = xdays ( 1job/4days + 1job/6days + 1job/2days)
Notice that I had to flip their rates to get the units to work out correctly.
1 job = xdays ( 11job/12days)
So
x = 12/11 where x has units of days.
2007-01-24 05:21:13 · answer #3 · answered by cp_exit_105 4 · 0⤊ 0⤋
Hi Bubbie,
Sam completes the work in 4 days. So he completes 25% of the work in a day.
Lisa completes the work in 6 days. So she completes 16.67% of the work in a day.
Tom completes the work in 2 days. So he completes 50% of the work in a day.
If they work together, they will complete 91.67% (25% + 16.66% + 50%) of the work in a day.
So, working together, they will complete it in 1day (91.67% completed) + 1/12th of a day (remaining 8.33 completed).
Therefore, the solution is:
1 day + 1/12th of a day.
2007-01-24 04:48:56 · answer #4 · answered by Saumya Gupta 1 · 0⤊ 1⤋
i like burgars............and pizza too
mmm....arent there any cartoons yet???!!!
2007-01-24 05:53:30 · answer #5 · answered by Anonymous · 0⤊ 0⤋