document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1189402>Question 1189402</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Machine A can do a job alone in 10 hours. Machine B can do the same job alone in 12 hours. Machine A is turned on at 6am Machine B is turned on at 9 a.m. Machine A breaks down at 10 a.m., and Machine B must finish the job alone. When will Machine B finish? </SPAN>\n" );
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document.write( "Let's say the task is to inspect 60 items.\r<BR>\n" );
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document.write( "Machine A can inspect 60 items in 10 hours. Its unit rate is 60/10 = 6 items per hour.\r<BR>\n" );
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document.write( "Machine B can inspect 60 items in 12 hours. Its unit rate is 60/12 = 5 items per hour.\r<BR>\n" );
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document.write( "Machine A runs from 6 AM to 10 AM, which is a duration of 4 hours. Over this timespan, the machine inspects 6*4 = 24 items.<BR>\n" );
document.write( "This leaves 60-24 = 36 items for Machine B to inspect.\r<BR>\n" );
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document.write( "Machine B can inspect 5 items per hour, and must inspect 36 of them. That means it needs 36/5 = 7.2 hours<BR>\n" );
document.write( "When dividing the number of items over the unit rate, the \"items\" unit cancels leaving just the hours.\r<BR>\n" );
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document.write( "7.2 hours = 7 hours + 0.2 hours<BR>\n" );
document.write( "7.2 hours = 7 hours + 0.2*60 min<BR>\n" );
document.write( "7.2 hours = 7 hours + 12 min\r<BR>\n" );
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document.write( "Machine B needs 7 hours and 12 minutes.<BR>\n" );
document.write( "Adding this duration onto 9:00 AM will get us to 16:12 in military time which is equivalent to 4:12 PM\r<BR>\n" );
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document.write( "<font color=red>Answer:  4:12 PM</font><BR>\n" );
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