1.Suppose that there are 100 students in your program, of whom 90 are right-handed. Two students are selected at random. What is the probability of the following events?

a)Both are right-handed.

b)Both are left-handed.

c)One is right-handed and the other is left-handed.

d)At least one is right-handed.

2.Three airlines serve a small town in Milwaukee. Airline X has 50% of all the scheduled flights, airline Y has 30% and airline Z has the remaining 20%. Their on-time rates are 80%, 65%, and 40% respectively. A plane has just left on time.

Draw a probability tree and insert the probabilities of each branch.What is the probability that the plane was airline X?