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math og 140

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math og 140

by resilient » Sat Mar 08, 2008 8:53 pm
machines a and b always operate independently and at their respective constant rates. When workin alone, machine a can fill a production lot in 5 hours, and machine b can fill the smae lot in x hours. When the two machines operate simultaneously to fill the production lot, it takes them 2 hours to complete the job. What is the value of x?

qa is 3 1/3


solution 1/5 +1/x= 1/2. Find x for solution. BUt wh 1/2. I dont see how setting it equal to 1/2 will fix the situation? How do I proceed to not make the same mistake again?
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by siddarthd2919 » Sat Mar 08, 2008 9:13 pm
hi engin i am pasting the formula.....this should help you


1/x+1/y=1/h

where x-----time taken for x to do the work alone

y-----time for y to do the work alone

h-----time taken for the work to be done when both x and y work together.
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ok

by resilient » Sun Mar 09, 2008 1:03 am
i see your point. I get it I know this formula. I guess I just got a bit mixwed up in the words. Here we are saying 1 job in 5 hours (a) + 1 job in X hours (B) = 1 job in 2 hours. Now simply find x whivh ever way you want. Either through algebra or backsolving. IS that the ticket?
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