SOLUTION: A,B, and C can finish a job in 6 days. If B and C work together, the job will take 9 days; if A and C work together, the job will take 8 days. In how many days can each man working
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-> SOLUTION: A,B, and C can finish a job in 6 days. If B and C work together, the job will take 9 days; if A and C work together, the job will take 8 days. In how many days can each man working
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Question 107942: A,B, and C can finish a job in 6 days. If B and C work together, the job will take 9 days; if A and C work together, the job will take 8 days. In how many days can each man working alone do the job? I was thinking about the equation:
A+B+C/6=1 Answer by edjones(8007) (Show Source):
You can put this solution on YOUR website! .
1/a+1/b+1/c=1/6 (1/6 means 1/6 of the job in 1 day)
1/b+1/c=1/9...1/b=1/9-1/c
1/a+1/c=1/8...1/a=1/8-1/c
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1/a+1/b+1/c=1/6
1/8-1/c+1/9-1/c+1/c=1/6
-1/c+1/8+1/9=1/6
-72+9c+8c=12c multiply both sides by 72
5c=72
c=72/5 days to do the job working alone.
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1/a=1/8-5/72
1/a=9/72-5/72=4/72
a=72/4 days
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1/b=1/9-5/72
1/b=8/72-5/72=3/72
b=72/3 days
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Check:
5/72+4/72+3/72=12/72=1/6
.
Ed
