The weights of cars passing over a bridge have a mean of 3550 lb and a standard deviation of 870 pounds. Assume that the weights of cars passing over the bridge or never distributed. Use the empirical rule to estimate the probability that a randomly-selected car going over the bridge will weigh less than 940 lbs

  a.  0.15%

Step-by-step explanation:

The Z-score of 940 pounds is ...

  (X -µ)/σ = (940 -3550)/870 = -3

The empirical rule tells you that 99.7% of the normal distribution lies within Z = ±3. Half of the remaining 0.3% lies below Z = -3, which is the set of weights of interest.

The probability that a car weighs less than 940 lbs is about 0.15%.