document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199453>Question 1199453</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Lynn and Farrah were asked to fill the tank with water. Lynn is twice faster than Farrah. Together, they filled it in two hours. How many hours can each of them alone fill the tank? </SPAN>\n" );
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document.write( "Lynn works twice as fast compared to Farrah.<BR>\n" );
document.write( "This means Lynn does 2/3 of the work when they team up.<BR>\n" );
document.write( "Farrah does the remaining 1/3.<BR>\n" );
document.write( "Note that 2/3 is twice that of 1/3; also the two fractions add to 1.\r<BR>\n" );
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document.write( "Consider a tank that is 24 gallons. You can pick any other multiple of 3.\r<BR>\n" );
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document.write( "Since Lynn does 2/3 of the work, she is able to fill (2/3)*24 = 16 gallons in 2 hours.<BR>\n" );
document.write( "Her unit rate is 16/2 = 8 gallons per hour.<BR>\n" );
document.write( "If Lynn worked alone, then she needs 24/8 = 3 hours to do the full job.\r<BR>\n" );
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document.write( "Relevant useful formulas<BR>\n" );
document.write( "rate = (amount done)/(time)<BR>\n" );
document.write( "time = (amount done)/(rate)\r<BR>\n" );
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document.write( "Farrah does 1/3 of the 24 gallons, so she fills (1/3)*24 = 8 gallons in 2 hours.<BR>\n" );
document.write( "rate = 8/2 = 4 gallons per hour<BR>\n" );
document.write( "If Farrah worked alone, then she would need 24/4 = 6 hours.<BR>\n" );
document.write( "Or note that since Lynn takes 3 hours, Farrah would take 2*3 = 6 hours since Farrah works for twice as long.\r<BR>\n" );
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document.write( "Answers:<BR>\n" );
document.write( "Lynn = <font color=red>3 hours</font><BR>\n" );
document.write( "Farrah = <font color=red>6 hours</font><BR>\n" );
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