Answer:
21794.495 units/month
Step-by-step explanation:
Some data are missing which i can assume as per requirement of the Question.
Let us consider that profit generated by a product is given by
p(x) =4√x
Also, consider that the profit keeps changing at a rate of $1000 per month.
Now, Using the chain rule we can write
dp/dx=(dp/dt)÷(dx/dt).
So, we can calculate
dp/dx=2x^(-1/2)=2/√x.
As per question we have to find out dx/dt
Since, dx/dt= (dp/dt)/(dp/dx),
so plugging x=1900 we get 1000√1900/2=21794.495 units/month increase in sales.