A study found that the mean amount of time cars spent indrive-throughs of a certainfast-food restaurant was 138.9 seconds. Assumingdrive-through times are normally distributed with a standard deviation of 30 seconds, complete parts(a) through(d) below.

(a) What is the probability that a randomly selected car will get through therestaurant's drive-through in less than 97 seconds?

The probability that a randomly selected car will get through therestaurant's drive-through in less than 97 seconds is

_______

.

(Round to four decimal places asneeded.)

(b) What is the probability that a randomly selected car will spend more than 178 seconds in therestaurant's drive-through?

The probability that a randomly selected car will spend more than 178 seconds in therestaurant's drive-through is

___________

.

(Round to four decimal places asneeded.)

(c) What proportion of cars spend between 2 and 3 minutes in therestaurant's drive-through?

The proportion of cars that spend between 2 and 3 minutes in therestaurant's drive-through is

____________

.

(Round to four decimal places asneeded.)

(d) Would it be unusual for a car to spend more than 3 minutes in therestaurant's drive-through?Why?

The probability that a car spends more than 3 minutes in therestaurant's drive-through is

________________

, so it

would

would not

beunusual, since the probability is

less

greater

than 0.05.

(Round to four decimal places asneeded.)