A trucking company has determined that, on an annual basis, the distance travelled per truck is normally distributed with a mean of 55 thousand kilometres and a standard deviation of 17.4 thousand kilometres.
a) What is the probability that the 22 trucks based in the Toronto office average at most 46 thousand kilometres? (0.0076)
b) There are 42 trucks based in the Montreal office, there is a 95% chance that the average annual distance driven by these trucks is more than how many kilometers? (50.58 thousand km.)