At a Highway Checkpoint,the Average Speed of a Passing Car

Multiple Choice

At a highway checkpoint,the average speed of a passing car was measured at 50 miles per hour with a standard deviation of 5 miles per hour.According to Chebyshev's Theorem,what percentage of cars would you expect to be traveling between 42.5 and 57.5 miles per hour?

A) at least 50%
B) at least 55.6%
C) at least 75%
D) at least 88.9%