Brief calculus.

Question

A company's revenue from selling x units of an item is given as R = 1600x-3x^{2 }

. If sales are increasing at a rate of 50 units per day, how rapidly is the revenue increasing per day when 210 units have been sold? (Solve this problem using related rates.)

Answer 1

dR/dt = (1600 - 6x)dx/dt = (1600 - 6·210)·50 = $17000 per day