At the moment OHaganBooks is selling 1000 books per week and its sales are rising at a rate of 200 books per week. Also, it is now selling all its books for $20 each, but the price is dropping at a rate of $1 per week. I need to know at what rate OHaganBooks' revenue is rising or falling given these conditions. I would also like to see the company's revenue increase at a rate of $5000 per week. At what rate would sales have to have been increasing to accomplish this?

Can somebody help me answer this and explain the steps to solve the problem?

3 answers

write the functions.

revenue= number books sold * price book

dRev/dt=n dp/dt + p dn/dt

you are given n, p and dp/dt, and dn/dt

calculate.
For the second part, set dRev/dt to 5000
find dn/dt given n, p, dp/dt

I will be happy to critique your work.
ok i got this
R=(1000+200x)(20-x)
R'=3000-400x
is that right so far?
and x=weeks?