In determining automobile mileage ratings, it was found that the fuel efficiency expressed in mpg (X) for a certain model is normally distributed, with a mean of 35 mpg and a standard deviation of 2.0 mpg.

What mileage rating does the best 10% of cars receive?

37.563

37.759

37.812

An entrepreneur opened a small store in a mall. During the first few weeks, business was slow, with the store averaging only one customer every 18 minutes in the morning. Assume that the random arrival of customers follows Poisson distribution, what is the probability that less than nine minutes elapse between customers?

0.388

0.393

0.399

The distribution of GMAT scores for an incoming class of business students has a mean of 670 and a standard deviation of 49.

Assuming that the scores are normally distributed, find the score that the top 5% of students will have.

780

750

720

Ship collisions in a harbour are rare.

Suppose the number of collisions is Poisson distributed, with a mean of 0.7 every four months.

What is the probability of having exactly 2 collisions in a two-month period?

0.034

0.043

0.957

The time required to play a game is uniformly distributed between 13 and 47 minutes. What is the probability that the game will take longer than 28 minutes to complete?

0.559

0.628

0.811