Probability Math Question?

I need help with this math question. I know I'm supposed to use the C(n,k) = n! / (n-k)! k! --but i dont know how to apply it. Here goes:





The probability of rain on a certain day is 70% in Yellow Falls, and 50% in copper creek.


Find each probability:


a.) P(It will rain in Yellow Falls, but not Copper Creek)


b.) P(It will rain in both cities)


c.) P(It will rain in neither city)


d.) P(It will rain in at least one of the cities)





You don't have to do all of them, but a step by step explanation of at least one would really help.

Probability Math Question?
To answer these questions you do NOT need to use the "combinatorial" formula. Actually, it doesn't even apply at all in these cases. The answers are:





a. 0.7 * (1-0.5) = 0.35 --%26gt; 35%


b. 0.7 * 0.5 = 0.35 --%26gt; 35%


c. (1-0.7) * (1-0.5) = 0.15 --%26gt; 15%


d. 1-((1-0.7)*(1-0.5)) = 0.85 --%26gt; 85%





where (1-p) is the probability of no rain in the given city. For example, (1-0.7) means no rain in Yellow Falls.
Reply:I could say not enough info..how far is yellow fall from copper creek...yet I say both cities for now