"A pharmaceutical company firm manufactures a liquid form of penicillin in bulk at a price of £200 per unit. The total production cost £$C$ for $x$ units is:
$$ C = 500,000 + 80x + 0.003x^2 $$
and the production capacity of the firm is at most 30,000 units in a specified time.
(a) Write down the revenue £$R$ the firm makes by selling $x$ units of penicillin."
I assume the profit made on each unit is 80$x$, but apart from that I'm not sure how I should go about interpreting and answering this. Thanks in advance.