Question 1127464
That also means, for every 1 dollar price increase,  {{{200/5}}} fewer subscriptions.

<pre>
PRICE         HOW MANY SUBSCRIPTIONS
40              2000
400+d          2000-(200/5)d

for d number of dollars
</pre>

Revenue,  {{{(40+d)(2000-(200/5)d)}}}.

You want to find the maximum of this revenue and the corresponding d number of dollars to add or subtract for this maximum d.


{{{40(40+d)(50-d)}}}

zeros at d of -40, and +50.


{{{(-40+50)/2=10/2=highlight_green(5)}}}



This means, best revenue is for {{{40+5=highlight(45)}}} dollars.
This max revenue,  {{{40*45*45=highlight(81000)}}}