There are two ways to get from City One to City Three, (a) directly or (b) via City Two. Let A be the event that the road from City One to Three is open. Similarly, B is for City One to Two and C is for City Two to Three. If snow is forecast for the next day, one can assume from past experience that Pr[A] = 0.6, Pr[B] = 0.7, Pr[C] = 0.4, Pr[C|B] = 0.5, and Pr[A|BC] = 0.4. Pr[A|BC] is the probability of A occuring conditional on BnC occuring. A, B, and C are NOT independent.
a) What is the probability that one can travel to City Three via City Two?
b) Which route ( One to Three or One to Two to Three) should you take? Explain
c) What is the probability that one can travel from City One to Three (directly OR via City Two)