document.write( "Question 56849: JOhn does a task in 30 minutes, Jennifer does in 45 minutes and Caryn in 1 1/2 hour. How long would it take for the three of them to do it if they do it together? \n" ); document.write( "

Algebra.Com's Answer #38596 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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JOhn does a task in 30 minutes, Jennifer does in 45 minutes and Caryn in 1 1/2 hour. How long would it take for the three of them to do it if they do it together?
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\n" ); document.write( "Get everything in minutes: Caryn 1.5 hr = 90 min
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\n" ); document.write( "Let the completed job = 1
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\n" ); document.write( "Let x = time required when they all work together:
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\n" ); document.write( "The equation:
\n" ); document.write( " $\"x%2F30+%2B+x%2F45+%2B+x%2F90\"$ = 1
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\n" ); document.write( "We can eliminate the denominators by mult eq by 90, we then have:
\n" ); document.write( "3x + 2x + x = 90
\n" ); document.write( "6x = 90
\n" ); document.write( "x = 15 minutes to complete the job:
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\n" ); document.write( "Check:
\n" ); document.write( "15/30 + 15/45 + 15/90 =
\n" ); document.write( "3/6 + 2/6 + 1/6 = 1
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