SOLUTION: An old printing press takes 5 hours longer to put out a daily paper than does a new press. If the two press work together, the job takes 6 hours. How long does it take each press t
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Question 1176203: An old printing press takes 5 hours longer to put out a daily paper than does a new press. If the two press work together, the job takes 6 hours. How long does it take each press to put out the paper on its own? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! An old printing press takes 5 hours longer to put out a daily paper than does a new press.
If the two press work together, the job takes 6 hours.
How long does it take each press to put out the paper on its own?
:
let t = time required by the new press to do the job
then
(t+5) = time required by the old press
let the completed job = 1
:
Each will do a fraction of the job, the two fractions add up to 1 + = 1
Multiply by t(t+5), cancel the denominators
6(t+5) + 6t = t(t+5)
6t + 30 + 6t = t^2 + 5t
12t + 30 = t^2 + 5t
form a quadratic on the right'
0 = t^2 + 5t - 12t - 30
t^2 - 7t - 30 = 0
Factors to
(t-10)(t+3) = 0
positive solution is all we want here
t = 10 hrs required by the new press
then, obviously
15 hrs required by to old press
:
:
See if that works + = + = 1
