Question 1091954
.
The first part of the condition 

<pre>
     A firm sells its product for R200 per unit. The cost per unit (per month) is 80 + x , where x represents the number of units sold per month. 
</pre>says about units per month.



The question 

<pre>
     What is the marginal profit at a production level of 20 units?
</pre>tells about units,  &nbsp;but not about  "units per month"  &nbsp;&nbsp;(as it should be).



==============>  &nbsp;&nbsp;It is not a way to formulate Math problem.




Math problems are not &nbsp;"playing words".
Math problems use precise formulations, &nbsp;that do not leave the room for questions &nbsp; &nbsp;"What is it  &nbsp;?"  &nbsp;&nbsp;or &nbsp;&nbsp;"What does it mean &nbsp;?"