goal760 Posted June 23, 2005 Share Posted June 23, 2005 In an 8-hour working day (Including pause time), a machine can finish 65 projects, 50 of which are 5-minute items, 15 of which are 15-minutes items. What is the probability that, in anytime of the day, the machine is working on the 15-minutes items? NO OA, let's discuss. Quote Link to comment Share on other sites More sharing options...
arjmen Posted June 23, 2005 Share Posted June 23, 2005 Assuming "anytime of the day" implies during the working hours: There are 8*60/5 = 96 5-minute periods. The 15 15-minute projects use 15*15/5 = 45 5-minute periods Therefore P(favourable event) = 45/96 = 15/32 Quote Link to comment Share on other sites More sharing options...
arangarajan Posted June 23, 2005 Share Posted June 23, 2005 total time : 8*60 = 480 mins. 5 mins job= 50 *5 = 250 mins for all the 5 mins job. 15 mins job: 15*15 = 225 mins pause time spent = 5 mins. probability for the 15 min job to be running = 225/480 =15/32 Here the pause time and the time taken for the 50 mins job is irrelevant as we know the total time as 480 min. Is this correct. can someone correct otherwise. Quote Link to comment Share on other sites More sharing options...
mananmehra Posted June 23, 2005 Share Posted June 23, 2005 Same answer different approach Total time in minutes= 480=total outcomes total time for 15 minute jobs =15*15= favourable outcomes At any time probablity for 15 minutes is-225/480=45/96=15/32 Quote Link to comment Share on other sites More sharing options...
pach2212 Posted June 24, 2005 Share Posted June 24, 2005 50*5 = 250 mins of 5 minutes job 15*15 = 225 mins of 15 minutes job Total working time = 475. Pause time = 480 - 475. So ratio of 5min : 15min : Pause = 250:275:5 = 50:45:1 So the probability that 15 mins job being performed will be 45/96 15/32 Quote Link to comment Share on other sites More sharing options...
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