Hi! Please help me. I'm reviewing for Exam P and I came across these questions which I can't solve (or rather, the answers that I get are wrong)

1. The claim amount on a certain insurance contract has a normal distribution with mean $3,300 and standard deviation $575. Given 25 independent claims, what is the probability that the number of claims less than $2700 is less than or equal to 4?

--> The answer key says 0.69 is the correct answer

2. An insurance company has a large block of one year term policies, which is divided into three classes of policies. The distribution of policies is 40% in class A, 50% in class B, and 10% in class C. The probability of death is 20% in class A, and 10% in classes B and C. Five policies are selected from the same class; it is observed that one of the five policyholders dies in the year. What is the probability that these policies are from class A?

--> The answer key says 0.571 is the correct answer (but I keep on getting 0.454)

3. What is the average age to which a 90-year old man will live, given that the probability a person age x will die before age x+1 is (x - 89) / 5?

--> The answer key says 95.1 is the correct answer

could you please tell me how to solve these problems correctly? Thank you very much!!

1. The claim amount on a certain insurance contract has a normal distribution with mean $3,300 and standard deviation $575. Given 25 independent claims, what is the probability that the number of claims less than $2700 is less than or equal to 4?

--> The answer key says 0.69 is the correct answer

2. An insurance company has a large block of one year term policies, which is divided into three classes of policies. The distribution of policies is 40% in class A, 50% in class B, and 10% in class C. The probability of death is 20% in class A, and 10% in classes B and C. Five policies are selected from the same class; it is observed that one of the five policyholders dies in the year. What is the probability that these policies are from class A?

--> The answer key says 0.571 is the correct answer (but I keep on getting 0.454)

3. What is the average age to which a 90-year old man will live, given that the probability a person age x will die before age x+1 is (x - 89) / 5?

--> The answer key says 95.1 is the correct answer

could you please tell me how to solve these problems correctly? Thank you very much!!

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