Pls help extra points and mark brainlist

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?

If there are 825 students at cherry hill high school and 4 out of every 5 students voted in the student council election, how many students voted?

In a rational number twice the numerator is 2 more than the denominator. if 3 is added to each, numerator and the denominator, the new fraction is 2/3. find the original number