What is the probability that a domestic airfare is $560 or more (to 4 decimals)? b. What is the probability that a domestic airfare is $260 or less (to 4 decimals)? c. What if the probability that a domestic airfare is between $320 and $500 (to 4 decimals)? d. What is the cost for the 3% highest domestic airfares? (rounded to nearest dollar)

(a)

(b)

(c)

Step-by-step explanation:

The first thing that you need to understand is how the random variable is distributed, it is normally distributed with mean cost  and standard deviation .

Now for (a)

We are looking for the following probability

Here is easier to work with the complement of it, so we get

Now we need to standardize that, for standardization we use the following formula

And here you have to grab a standard normal table and see what is that probability.

Now, if you want to interpret that result in terms of intuition, that means that the event is very unlikely.

(b)

You are looking for the following probability

(c)

You are looking for the following probability

i think it is x = 1.2

the answer is b.

step-by-step explanation: