Please help with a b and c

5.21. Stock traders buy stocks in order to sell at a profit. Suppose that based on previous trades, the probability that a particular stock trader will make a profit from a stock purchase is 0.71. A sample of 15 trades is selected. a. What is the probability that 11 trades will make a profit? b. What is the probability that more than 13 trades will make a profit? c. What is the probability that 8 to 10 (inclusive) trades will make a profit