Question
An experiment succeeds thrice as often as it fails. Find the probability that in the next five trials, there will be at least 3 successes.
Solution
An experiment succeeds as often as it fails.
Therefore, there are 3 successes and 1 failures.
Thus the probability of success 
And the probability of failure = 
We need to find the probability of atleast 3 successes in the next five trials.
Required Probability = P(X= 3) + P(X = 4) + P(X = 5)
