SOLUTION: Machine A can photocopy 1000 pieces of a single file in 5 hours,
while Machine B can photocopy 1000 pieces of the same file in 4
hours. How long will it take the two machines, bo
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-> SOLUTION: Machine A can photocopy 1000 pieces of a single file in 5 hours,
while Machine B can photocopy 1000 pieces of the same file in 4
hours. How long will it take the two machines, bo
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Question 1094523: Machine A can photocopy 1000 pieces of a single file in 5 hours,
while Machine B can photocopy 1000 pieces of the same file in 4
hours. How long will it take the two machines, both working
together to photocopy 1,600 pieces of a file?
please include full solution for future self-study
Thank you!! Found 2 solutions by greenestamps, ikleyn:Answer by greenestamps(13196) (Show Source):
You can put this solution on YOUR website! 1000 pieces in 5 hours --> 200 per hour.
1000 pieces in 4 hours --> 250 per hour.
Together: 450 per hour.
1600 pieces, at 450 per hour --> 1600/450 hours.
32/9 hours, or 3 5/9 hours, or 3 hours 33 1/3 minutes.
Or an alternative method of solving the problem....
A takes 5 hours to do 1000 pieces, so it does 1/5 of the job in 1 hour.
B takes 4 hours to do 1000 pieces, so it does 1/4 of the job in 1 hour.
Together in 1 hour, the fraction of the job A and B do in 1 hour is
and so the number of hours it takes them to do the job together is 20/9.
But that job is 1000 pieces; this job is 1600 pieces. So we need to multiply the amount of time by 1600/1000, or 8/5:
