document.write( "Question 1191917: Wilma can mow the lawn in 3 hours. If Kyle helps her with another mower, the lawn can be mowed in 2 hours. How long would it take Kyle if he worked alone? \n" ); document.write( "
Algebra.Com's Answer #823765 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Let's say the lawn is 120 square feet.\r
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\n" ); document.write( "\n" ); document.write( "Wilma can mow the lawn in 3 hours when working alone.
\n" ); document.write( "Her unit rate is 120/3 = 40 sq ft per hour.
\n" ); document.write( "In other words, she can mow 40 square feet in one hour.\r
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\n" ); document.write( "\n" ); document.write( "If Kyle helps her, and the two don't hinder each other, then their combined unit rate is 120/2 = 60 sq ft per hour since they can get the job done in 2 hours.\r
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\n" ); document.write( "\n" ); document.write( "This must mean Kyle's unit rate when he works alone is 60-40 = 20 sq ft per hour.
\n" ); document.write( "Put another way: The two workers, when doing the task alone, must have their sole unit rates add to the combined unit rate.\r
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\n" ); document.write( "\n" ); document.write( "Since Kyle works alone to mow the grass at a rate of 20 sq ft per hour, and must mow 120 sq ft, then he'll need 120/20 = 6 hours to do the job when working alone.\r
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\n" ); document.write( "\n" ); document.write( "An alternative approach is to solve the equation
\n" ); document.write( "1/3 + 1/x = 1/2
\n" ); document.write( "and you should find the solution is x = 6\r
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\n" ); document.write( "\n" ); document.write( "Answer: 6 hours
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