In a certain college the geographical distribution of men students is as follows: 50% come from the East, 30% come from the Midwest, and 20% come from the Far West. The following· proportions of the men students wear ties: 80% of the Easterners, 60% of the Midwesterners, and 40 % of the Far Westerners. What is the probability that a student who wears a tie comes from the East? From the Midwest? From the Far West?