document.write( "Question 78502: It takes me 3 hours to prepare a special dinner in class, when it only took my husband 2 hours. How long will it take for them both to finish the cooking class? Answer should be rounded to the one decimal. Must be shown in a rational equation \n" ); document.write( "
Algebra.Com's Answer #56295 by bucky(2189)\"\" \"About 
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You have 1 job ... and that job is cooking the meal. Since you take 3 hours to do that job,
\n" ); document.write( "your rate of doing it is \"1%2F3\" of the job per hour. Your husband does the 1 job in
\n" ); document.write( "2 hours, so his rate of doing the job is \"1%2F2\" of the job per hour. When you work together
\n" ); document.write( "your time to complete the 1 job is represented by t. The equation becomes:
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\n" ); document.write( "\"%281%2F3%29%2At+%2B+%281%2F2%29%2At+=+1+\" where the 1 represents the entire job.
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\n" ); document.write( "You can add the terms on the left side either by converting the fractions to decimals or
\n" ); document.write( "by putting them over the common denominator of 6. Let's use the common denominator.
\n" ); document.write( "Recognize that \"1%2F3+=+2%2F6\" and \"1%2F2+=+3%2F6\". Substituting these values makes the
\n" ); document.write( "equation become:
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\n" ); document.write( "\"%282%2F6%29%2At+%2B+%283%2F6%29%2At+=+1\"
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\n" ); document.write( "Now add the two terms on the left side to result in:
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\n" ); document.write( "\"%282%2B3%29%2F6%2At+=+1\"
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\n" ); document.write( "and this simplifies to:
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\n" ); document.write( "\"5%2F6%2At+=+1\"
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\n" ); document.write( "you can then solve for t by dividing both sides of this equation by \"5%2F6\" to get:
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\n" ); document.write( "\"+t+=+1%2F%285%2F6%29\" and then apply the rule that dividing a quantity by a fraction
\n" ); document.write( "is the same as multiplying the quantity by the inverse of the fraction. This converts
\n" ); document.write( "the equation for t to:
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\n" ); document.write( "\"t+=+1%2A%286%2F5%29+=+6%2F5\"
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\n" ); document.write( "and when you divide 5 into 6 you get an answer of 1.2 hours. That's the answer ...
\n" ); document.write( "if you and your husband work together you should finish the class in 1.2 hours.
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\n" ); document.write( "Hope this helps you to understand problems of combined efforts a little better.
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