A trucking company determined that the distance traveled per truck per year is normally distributed, with a mean of 60 thousand miles and a standard deviation of 12 thousand miles. Complete parts (a) through (d) below. a. What proportion of trucks can be expected to travel between :14 and 50 thousand miles in a year? The proportion of trucks that can be expected to travel between 44 and 50 thousand miles in a year is 0.4088'. (Round to fourdecimal places as needed.) b. What percentage oftrucks can be expected to travel either less than 50 or more than 60 thousand miles in ayear? The percentage oftrucks that can be expected to travel either less than 50 or more than E0 thousand miles in ayear is 25.08 941. (Round to two decimal places as needed.) c. How many miles will he traveled by at least 60% ofthe trucks? The number of miles that will he traveled by at least 60% of the trucks is 57000 miles. (Round to the nearest mile as needed.) d. What are your answers to parts (a) through (c) if the standard dewation is 8 thousand miles? If the standard dewation is 8 thousand miles, the proportion of trucks that can be expected to travel between :14 and 60 thousand miles in a year is (Round to fourdeCImal places as needed.)