Please help I would appreciate it

Ineed to know the answer right now! !

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250

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?