document.write( "Question 344715: I need help with word problems. The first one is: You can paint a certain room in 5 hours. Your brother can do it in 2 hours. How long does it take the two of you working together?
\n" ); document.write( "I thought that by adding 5 and 2 and then dividing that by 2 would give me the correct amount, but this is wrong. thank you.
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Algebra.Com's Answer #246664 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

You can put this solution on YOUR website!
The first one is: You can paint a certain room in 5 hours.
\n" ); document.write( " Your brother can do it in 2 hours. How long does it take the two of you working together?
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\n" ); document.write( "This is a typical \"shared work\" problem and can be done this way
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\n" ); document.write( "Let t = time required when working together
\n" ); document.write( "Let the completed job = 1
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\n" ); document.write( "Each person will do a fraction of the job, the two fractions add up to 1
\n" ); document.write( "so we have:
\n" ); document.write( " $\"t%2F5\"$ + $\"t%2F2\"$ = 1
\n" ); document.write( "Multiply thru by 10 to get rid of the denominators, results:
\n" ); document.write( "2t + 5t = 10
\n" ); document.write( "7t = 10
\n" ); document.write( "t = $\"10%2F7\"$
\n" ); document.write( "t ~ 1.43 hrs or about 1 + .43(60) = 1 hr 26 min
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\n" ); document.write( "You can confirm this on a calc
\n" ); document.write( "1.43/5 = .286
\n" ); document.write( "1.43/2 = .715
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\n" ); document.write( "totals: 1.000
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