Answer:
25% probability that all three residents will choose the same plumbe
Step-by-step explanation:
For each resident, there are only two possible outcomes. Either they choose the first plumbe, or they choose the second. The plumbers are chosen independent of each other. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
Each resident randomly chooses one of the two plumbers.
This means that
Three residents:
This means that
What is the probability that all three residents will choose the same plumb
This is P(X = 0)(all choose the second pumble) or P(X = 3)(all choose the first pumble). So
25% probability that all three residents will choose the same plumbe