A radar unit is used to measure the speed of automobile on an expressway during rush-hour traffic. The speeds of individual automobiles are normally distributed with a standard deviation of 6 mph.

a) Find the mean of all speeds if 7% of the automobiles travel faster than 75 mph. Report the mean to the nearest tenth.

b) Using the mean answer you found in part a, find the probability that a car is traveling between 70 mph and 75 mph. Report your answer to 3 decimal places.

c) Using the mean answer you found in part a, find the 25th percentile for the variable "speed". Report your answer to the nearest tenth.