21. TENNIS A double fault in tennis is when the serving player fails to land their serve "in" without stepping on or over the service line in two chances. Kelly's first serve percentage is 40%, while her second serve percentage is 70%. a. Draw a probability tree that shows each outcome. b. What is the probability that Kelly will double fault? c. Design a simulation using a random number generator that can be used to estimate the probability that Kelly double faults on her next serve