__________________________________________________________________

**Problem 27A**

For a certain brand of light bulbs, the time (in thousands of hours) until the instant a light bulb burns out follows an exponential distribution. From past experience, we know that of the light bulbs will go out within 500 hours of use. What proportion of the light bulbs can be expected to go out within 1000 hours of use?

**Problem 27B**

In the emergency room of a large hospital in a metropolitan area, the wait time (in hours) to see a doctor follows an exponential distribution. From past experience, 40% of the wait times are 3 hours or less. What proportion of the patients in the emergency room can be expected to wait more than 15 hours to see a doctor?

__________________________________________________________________

__________________________________________________________________

**Answers**

__________________________________________________________________

### Like this:

Like Loading...

*Related*