Question 894307
R rate for 1 man
r rate for 1 woman


{{{12*R*6=1}}}; {{{(10R+21r)*3=1}}} because their rates are summed when working together.
These two equations are a system using the two variables, r and R.
Use the first one to find R, and use this now known R to find the value for r.


{{{R=1/(12*6)}}}
{{{highlight_green(R=1/72)}}}
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{{{(10/72+21r)*3=1}}}
{{{10/24+63r=1}}}
{{{63r=1-10/24}}}
{{{63r=1-5/12=12/12-5/12}}}
{{{63r=7/12}}}
{{{r=7/(63*12)}}}
{{{r=1/(9*12)}}}
{{{highlight_green(r=1/108)}}}
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The question is, how many days  (t = time in DAYS)  for 12 women to do 1 job?


{{{12(1/108)*t=1}}}
{{{t=108/12}}}
{{{highlight(t=9)}}}  DAYS