The price of a certain computer stock t days after it is issued for sale is p(t)=100+20t-3t^2 dollars. The price of the stock initially rises, but eventually begins to fall.
a) During what period of time does the stock price rise? I have already figured out that... dp(t) / dt = 20 - 6t = 0
6t = 20
t = 20/6 = 3.33 but I am not sure how to find the answer to b
b) If you owned the stock, after how many days would you sell it?