SOLUTION: Three machines are filling water bottles. The machines can fill the daily quota of water bottles in 12 h, 15 h, and 20 h, respectively. How long would it take to fill the daily quo

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Question 733515: Three machines are filling water bottles. The machines can fill the daily quota of water bottles in 12 h, 15 h, and 20 h, respectively. How long would it take to fill the daily quota of water bottles with all three machines working?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
1/12 + 1/15 + 1/20 = 1/t

5/60 + 4/60 + 3/60 = 1/t

(5+4+3)/60 = 1/t

12/60 = 1/t

1/5 = 1/t

1*t = 5*1

t = 5

So if all machines are working together (with no one machine hindering the other), then they will fill the quota in 5 hours.