Fast Service Truck Lines uses the Ford Super 1310 exclusively. Management made a study of the maintenance costs and determined the number of kilometres travelled during the year followed the normal distribution. The mean of the distribution was 96 600 km and the standard deviation 3200 km.
a. What percentage of the Ford Super 1310s logged 104 970 km or more?
b. What percentage of the trucks logged more than 95 500 but less than 96 000 km?
c. What percentage of the Fords travelled 99 800 or less during the year?
d. Is it reasonable to conclude that any of the trucks were driven more than 112 700 km? Explain.