Answer:
0.2149 is the probability that for exactly three calls, the lines are occupied.
Step-by-step explanation:
We are given the following information:
We treat phone line being occupied as a success.
P(Adult need eye correction) = 40% = 0.40
Then the number of phone lines follows a binomial distribution, where
[tex]P(X=x) = \binom{n}{x}.p^x.(1-p)^{n-x}[/tex]
where n is the total number of observations, x is the number of success, p is the probability of success.
Now, we are given n = 10
We have to evaluate:
[tex]P(x = 3) = \\= \binom{10}{3}(0.40)^3(1-0.40)^7 \\= 0.2149[/tex]
0.2149 is the probability that for exactly three calls, the lines are occupied.
