The cost and revenue functions are given as:
\[
C(x) = 3x^2 + 5x + 200, \quad R(x) = 50x
\]
Find the number of items that should be sold to maximize the profit.
Show Hint
To maximize profit, differentiate the profit function and find critical points using \( P'(x) = 0 \). Check values around it to find maximum.