Question 1020353
RT=J relates work rate, time, amount of job or work.  Your example uses 1 for the amount of work of making ONE chair.


The rate for more than one identical working agents acting simultaneously on the same task is the sum of their rates.

<pre>
Carpenter     Rates

A           {{{1/6}}}

B           {{{1/9}}}</pre>

How long t, for the two of them to finish AFTER carpenter B joins?


{{{(1/6)*2+(1/6+1/9)*t=1}}}