This kind of problems are solved using Bernoulli's distribution. Everytime you have a win/lose scenario, and you know the probability 
of winning, and you want 
successes over 
trials, you have the following probability:
You want the probability of having at least three successes, i.e. you are interested in the cases k=3 and k=4. The corresponding probabilities are
So, the total probability is 
Answer:
I'm sorry but the question is not clear enough for me to understand the question asked snap the entire question
Your answer is D because his line needs to be slightly above +25 each time 50+25=75 so his line would be above 75
