Can anyone help me what Formulas we use for those questions. I only need formulas not calculation.

1. In one of our student's data, there is a 25% chance someone will receive a starting pay above 40,200 Danish Krones.

a. Say we randomly sample from the data until we find two people who achieved a starting pay above 40,2000 Krones. What is the probability that we will need to sample at most 10 data points?

b. If we instead randomly sample 10 data points, what is the probability that 5 of the sampled salaries will be above 40,200 Krones?

2. Say you play two games of Guilty Gear, the first with character Baiken whom you have a 51% win rate with, and the second with character I-No, whom you have a 50% win rate with. Say that the probability that you win both games is 30%. Are your games independent? Mathematically justify your answer.