Question 1000927
{{{1/(1/4+1/6)}}}



The combined rate of both machines working together is the sum of their individual rates.  The unit of rate will be in FIELD per DAY.

<pre>
Machine          RATE in Fields per Day
Tractor           1/4
Smaller Tractor   1/6
</pre>

The rate for both working together is  {{{1/4+1/6}}} but you want the number as DAYS per FIELD, and this would be the reciprocal of  {{{1/4+1/6}}}, so that means  {{{1/(1/4+1/6)}}}  DAYS for 1 field.


This question is not about finding any equation, but only handling a rate.  Maybe you wanted something like D is how many days, and  1 field would be done according to rate {{{1/D}}}, and then  {{{1/4+1/6=1/D}}}?