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A car insurance company has determined that 7% of all drivers were involved in a car accident last year. Among the 12 drivers living on one particular street, 3 were involved in a car accident last year. If 11 drivers are randomly selected, what is the probability of getting 3 or more who were involved in a car accident last year?

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This is a binomial probability problem with n=11 (the number of drivers selected) and p=0.07 (the probability that a driver was involved in an accident).

To find the probability of getting 3 or more drivers who were involved in an accident, we need to find the probability of getting 3, 4, 5, ..., 11 drivers who were involved in an accident and then add those probabilities together.

We can use the binomial probability formula to calculate each of these individual probabilities:

P(X=k) = (n choose k) * p^k * (1-p)^(n-k)

where X is the number of drivers who were involved in an accident, k is the number of drivers we want to calculate the probability for, and (n choose k) is the binomial coefficient, which is calculated as:

(n choose k) = n! / (k! * (n-k)!)

Using this formula, we can calculate the probability of getting exactly k drivers who were involved in an accident.

For k=3, we have:

P(X=3) = (11 choose 3) * 0.07^3 * 0.93^8 = 0.1038

For k=4, we have:

P(X=4) = (11 choose 4) * 0.07^4 * 0.93^7 = 0.0286

For k=5, we have:

P(X=5) = (11 choose 5) * 0.07^5 * 0.93^6 = 0.0052

For k=6, we have:

P(X=6) = (11 choose 6) * 0.07^6 * 0.93^5 = 0.0007

For k=7, 8, 9, 10, 11, we have:

P(X=7) = (11 choose 7) * 0.07^7 * 0.93^4 = 0.0001

P(X=8) = (11 choose 8) * 0.07^8 * 0.93^3 = 0.0000

P(X=9) = (11 choose 9) * 0.07^9 * 0.93^2 = 0.0000

P(X=10) = (11 choose 10) * 0.07^10 * 0.93^1 = 0.0000

P(X=11) = (11 choose 11) * 0.07^11 * 0.93^0 = 0.0000

To get the probability of getting 3 or more drivers who were involved in an accident, we need to add up the probabilities for k=3, 4, 5, ..., 11:

P(X>=3) = P(X=3) + P(X=4) + P(X=5) + P(X=6) + P(X=7) + P(X=8) + P(X=9) + P(X=10) + P(X=11)

P(X>=3) = 0.1393

Therefore, the probability of getting 3 or more drivers who were involved in an accident out of 11 randomly selected drivers is 0.1393, or about 13.93%.

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