Probability review.

1. I Can't Wait ...
Pi Pie by megpi

2. There are 9 points marked in a plane, no three of which lie in a
straight line.
(a) How many straight lines can be drawn, each containing 2 of the points?
(b) How many of these pass through one or more of 3 specified points
in the set?
(c) What is the probability that a randomly chosen line will pass
through one or more of these 3 specified points?

4. While on vacation, I may lose part of my luggage and I may see a polar
bear. The probability of losing part of my luggage is 0.1 and the
probability of seeing a polar bear is 0.6. Draw a tree diagram to show
all possible outcomes when these two events are combined.