Problema Solution
A high speed printing press can produce the daily newspaper in 6 hours running alone. A second press could produce the daily run in 9 hours alone. it takes the old press 12 hours alone to produce the newspaper. a late breaking new story causes the headlines to change. If all 3 presses are used, how long will it take to produce the newspaper?
Answer provided by our tutors
The high speed printing press has an hourly rate of: 1/6 per hour
The second printing press has an hourly rate of: 1/9 per hour
The old press had an hourly rate of: 1/12 per hour
Let 'x' represent the time needed when all 3 presses are used.
The together hourly rate is 1/x per hour.
Now we can write:
1/6 + 1/9 + 1/12 = 1/x
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click here to see the equation solved for x
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x = 36/13 hr
x = 2 10/13 hr
x = 2 hr 10*60/13 min
x = 2 hr 46 min
2 hours and 46 minutes are needed if all 3 presses are used.