Find the rate of change of the quantity demanded of the

Question

Question: DEMAND FOR WATCHES The demand equation for the Sicard wristwatch is given by

x = f(p) = 10√(50 - p)                (0 < p ≤ 50)
                 √     p

where x (measured in units of a thousand) is the quantity demanded each week and p is the unit price in dollars. Find the rate of change of the quantity demanded of the wristwatches with respect to the unit price when the unit price is $25.