financial mathematics

3- Suppose the expected return from a stock is 14% per annum and the volatility is 20%. Initial stock price is 90$. Calculate the increase in the stock price during three days. 4- Suppose that a stock price has an expected return of 36% per annum and volatility of 40%. When the stock price at the end of certain day is 80$, calculate the following: a-The expected stock price at the end of the next day. b- the standard deviation of the stock price at the end of next day