During a recent year, there were 11.2 million automobile accidents, 5.7 million truck accidents, and 172,000 motorcycle accidents. Find the following probabilities. (a) If one accident is selected at random, find the probability that it is either a truck or motorcycle accident. P (truck or motorcycle accident)= (b) If one accident is selected at random, find the probability that it is not a truck accident. P (not truck accident)=