The demand function for a certain children bicycle is given by $$Q = 10 \sqrt{(50-p)/p}$$ where $Q$ is the quantity demanded per week and $p$ with $0 < p < 50$ is the price of a bicycle in dollars.

(a) Evaluate the demand elasticity $E$ at $p=40$.
$E(40)=$

Here, "demand elasticity" is the absolute value of $\displaystyle \frac{\text{percent change in quantity}}{\text{percent change in price}}$ for an infinitesimal change in price, so $$E = \left| \lim_{\Delta p \to 0} \frac{ \Delta Q / Q}{\Delta p / p} \right| \ .$$

(b) Should the price be raised slightly from 40 in order to increase revenue? ?? Yes No

(c) When is the demand elasticity unitary?
$p=$

(d) What is the maximum revenue?
Maximum Revenue =