Need to find Maximum Profit and Revenue Have Demand Function and Expense Function

Question

I am new to business Mathematics, Can I anyone help me understand how to solve the following problems.

Product demand function :

    q(p) = 900 – 3p
p – price of one product 
q – sold amount of a product with the p (price)

The input (expenses) function:

C(q) = 90 + 2q

Using second derivative find the revenue and profit maximum.

Can anyone help me how can I solve this, I have read some good answer to somewhat relevant question here but I am unable to grasp the concept

Answer 1

Here are some useful formulae to help you get started:

Revenue is just the total income (without accounting for cost). So here, this is just the number of units sold times the price you sold them for, i.e. $R(p)=p\times q(p)$.

Profit takes into account the cost, so it will just be $P(p)=R(p)-C(q(p))$. Hope this helps!

Also, if you need help with derivatives, just remember the power rule $\frac{d}{dp} p^k = kp^{k-1}$