document.write( "Question 885611: Lala and Baba can finish stacking 200 cups together in 12/5 hrs. One day, Baba stacked by herself. An hour later, Lala joined and they finished the job in 9/5 hrs. If Lala works alone and stacks all 200 cups, how many hours would it take her? \n" ); document.write( "

Algebra.Com's Answer #535302 by josgarithmetic(39617) $\"\"$ $\"About$

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The ONE job is to stack 200 cups. \r
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\n" ); document.write( "\n" ); document.write( "Lala AND Baba, $\"1%2F%2812%2F5%29\"$ jobs per hour
\n" ); document.write( "Lala, unknown, $\"1%2FL\"$ jobs per hour for some unknown L hours
\n" ); document.write( "Baba, unknown, $\"1%2FB\"$ jobs per hour for unknown time L.
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\n" ); document.write( "Baba for 1 hour and then both for the $\"9%2F5\"$ hours for doing 1 job:
\n" ); document.write( " $\"highlight_green%28%281%2FB%29%2A1%2B%281%2F%2812%2F5%29%29%2A%289%2F5%29=1%29\"$
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\n" ); document.write( "You can also form an equation for the sum of the combined rates of Baba and Lala:
\n" ); document.write( " $\"highlight_green%281%2FL%2B1%2FB=12%2F5%29\"$
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\n" ); document.write( "Those are two linear equations (they will be more obviously when you simplify them) in two unknowns, L and B. Just solve the system. L is the time for Lala to do the one job alone and B is the time for Baba to do the job alone. \n" ); document.write( "

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