A study found that the mean amount of time cars spent in drive-throughs of a certain fast-food restaurant was

137.7

seconds. Assuming drive-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 the restaurant's drive-through in less than

101

seconds?

The probability that a randomly selected car will get through the restaurant's drive-through in less than

101

seconds is

enter your response here

.

(Round to four decimal places as needed.)

(b) What is the probability that a randomly selected car will spend more than

188

seconds in the restaurant's drive-through?

The probability that a randomly selected car will spend more than

188

seconds in the restaurant's drive-through is

enter your response here

.

(Round to four decimal places as needed.)

(c) What proportion of cars spend between

2

and

3

minutes in the restaurant's drive-through?

The proportion of cars that spend between

2

and

3

minutes in the restaurant's drive-through is

enter your response here

.

(Round to four decimal places as needed.)

(d) Would it be unusual for a car to spend more than

3

minutes in the restaurant's drive-through? Why?

The probability that a car spends more than

3

minutes in the restaurant's drive-through is

enter your response here

,

so it

would

would not

be unusual, since the probability is

greater

less

than 0.05.