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If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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10 May 2012, 04:14
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If it takes 6 identical printing presses exactly 4 hours to print 5,000 newspapers, how long would it take 3 of these presses to print 3,000 newspapers? A. 3 hours, 20 minutes B. 4 hours, 20 minutes C. 4 hours, 48 minutes D. 5 hours, 48 minutes E. 6 hours, 50 minutes
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Re: Work rate problem [#permalink]
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10 May 2012, 04:22
piyushksharma wrote: If it takes 6 identical printing presses exactly 4 hours to print 5,000 newspapers, how long would it take 3 of these presses to print 3,000 newspapers?
A. 3 hours, 20 minutes B. 4 hours, 20 minutes C. 4 hours, 48 minutes D. 5 hours, 48 minutes E. 6 hours, 50 minutes 6 presses  5,000 newspapers  4 hours ; 3 presses  2,500 newspapers  4 hours ; 3 presses  3,000 newspapers  4 hours + 1/5*4 hours = 4 hours, 48 minutes (since 2,500+1/5*2,500=3,000). Answer: C.
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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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28 Sep 2013, 02:08
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00:46 time taken to solve Rate (6 machines) = 5000/4 Rate ( 1 machine) = 5000/24 Rate ( 3 machine ) = 5000/8 Rate * Time = Work 5000/8 * Time = 3000 Hence (C) !
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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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28 Sep 2013, 02:28
piyushksharma wrote: If it takes 6 identical printing presses exactly 4 hours to print 5,000 newspapers, how long would it take 3 of these presses to print 3,000 newspapers?
A. 3 hours, 20 minutes B. 4 hours, 20 minutes C. 4 hours, 48 minutes D. 5 hours, 48 minutes E. 6 hours, 50 minutes It is easier in this type of problems to find for unit measures and then find for the asked numbers. 1. 1 press would take 6*4 = 24 hours for 5000 newspapers 2. 1 press would take 24/5000 hrs for 1 newspaper 3. 3 presses would take 24/ (3* 5000) hrs for 1 newspaper 4. 3 presses would take 24*3000 / (3*5000) for 3000 newspapers i.e., 4.8 hrs which is 4 hours and 48 minutes.
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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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01 May 2014, 20:51
I took the following approach.. Let e be the efficiency of each machine and t be the time that we need to find out. So according to the question 6*e*4 = 5000 (given) e = 5000/24    1 Now you have the efficiency with you.. Simply solve for t.. 3*e*t = 3000 t = 3000/(3*e) From 1 t = 3000*24/3*5000 t = 4.8 hours 4 hours + 0.8*60 minutes 4 hours 48 minutes. Option C is right



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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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01 May 2014, 23:49
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Alternative way: The PTW Formula PT/W = PT/W where: P = printer T = time W = work (newspapers) (6)(4)/5000 = 3T/3000 Then use rapid cancellations: 24/5000 = T/1000 24/5 = T T = 4 4/5 hrs = 4 hrs 48 mins Hope it helps! Wacks Formula  Math Shortcuts



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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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18 Mar 2016, 22:42
piyushksharma wrote: If it takes 6 identical printing presses exactly 4 hours to print 5,000 newspapers, how long would it take 3 of these presses to print 3,000 newspapers?
A. 3 hours, 20 minutes B. 4 hours, 20 minutes C. 4 hours, 48 minutes D. 5 hours, 48 minutes E. 6 hours, 50 minutes In 1 hour 1 press prints 208 and 1/3 newspapers (given) In 3 hours 3*208 and 1/3 = 625 newspapers To print 3000 newspapers 3000/625 = 4 hours 48 min



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Re: If it takes 6 identical printing presses exactly 4 hours to [#permalink]
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05 Feb 2018, 11:11
Hi All, Since we have 6 machines working 4 hours each, we have 24 machinehours of work being done. Those 24 hours of machinework will produce 5,000 newspapers, so we can calculate what 1 hour of machinework will produce: 5,000/24 = 2,500/12 = 1250/6 = 625/3 newspapers per machinehour of work With 3 machines, we have (625/3)(3) = 625 newspapers produced per hour. We're asked how many hours is takes to produce 3,000 newspapers under these conditions... 3,000/625 = 600/125 = 120/25 = 24/5 hours = 4 4/5 hours = 4 hours 48 minutes Final Answer: GMAT assassins aren't born, they're made, Rich
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