Answer:
0.91 = 91% probability of you making it home for the holidays
Explanation:
You can make home with two possibilities:
With US-Scareways, with a 100 - 30 = 70% probability.
In the 30% that you cannot make it with US-Scareways, there is a 70% probability you can get a ride back with Walter.
What is the probability of you making it home for the holidays?
0.91 = 91% probability of you making it home for the holidays