In a metropolitan area, one out of ten drivers on the road on Saturday after midnight is intoxicated. Half of all accidents during this time period involve drunk drivers. Finally, the overall accident rate on Saturday after midnight is 3 accidents per 100 cars on the road. For a drunk driver, the risk of accident is:
A) .10.
B).15.
C) .50.
D).03
E) .05

Question

Quizplus · Accepted Answer

The probability of an accident given a driver is drunk is calculated by dividing the probability of an accident involving a drunk driver by the probability of a driver being drunk. The probability of an accident involving a drunk driver is 0.5 * 0.03 = 0.015. The probability of a driver being drunk is 0.1. Therefore, the risk of accident for a drunk driver is 0.015 / 0.1 = 0.15.

In a Metropolitan Area, One Out of Ten Drivers on the Road