<PRE><B>Question 684008</B>
Let x = time it takes them to do the job together.


{{{1/3.5+1/2 = 1/x}}}


First fraction is UGLY, so multiply numerator and denominator by 2 to clear the decimal:


{{{2/7 + 1/2 = 1/x}}}


Next, add the fractions with LCD = 14:

{{{4/14 + 7/14 = 1/x}}}


{{{11/14=1/x}}}


Invert the fractions:

{{{14/11 = x/1}}}

x= 14/11 hours


Dr. Robert J. Rapalje, Retired
Seminole State College of Florida


www.mathinlivingcolor.com.
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