During a football game kevin gained five yards on the first play then he lost seven yards on the second play how many yards does kevin need on the next play to get the team back to were they were when they started show your work

Margie is practicing for an upcoming tennis tournament. her first serve is good 20 out of 30 times on average. margie wants to know the estimated probability that her first serve will be good at least four of the next six times she serves. how could she design a simulation for this scenario?