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 
Yes, this is all correct!
Answer:
6%
Step-by-step explanation:
3/20=4/x
It is a indirect proportion so we reciprocal,
Then,
3/20=x/40
3×40=20×x
120=20x
x=120/20
x=6
Answer:
27.5%
Step-by-step explanation:
you take 0.275 and multiply it by 100 to get the percentage.
Step-by-step explanation:
