A trucking company determined that the distance traveled per truck per year is normally distributed, with a mean of 80 thousand miles and a standard deviation of 12 thousand miles. Complete parts (a) through (c) below. a. What proportion of trucks can be expected to travel between 64 and 80 thousand miles in a year? The proportion of trucks that can be expected to travel between 34 and 30 thousand miles in a year is (Round to four decimal places as needed.)