# Event and Sets Formulas help

#### nickar1172

##### New member
Which formula's would you use to solve each set and please show the actual formulas please thank you for the help I really appreciate it as I need to know this for my final exam tomorrow, thank you!

a) solving for neither set A and neither set B

b) Solving for set A or Set B, but not both

c) Solving for set B given set A

d) Solving for set B given that he does not have Set A

#### Jameson

Staff member
Hi again,

I probably need some more information. Are you simply asked to write these concepts mathematically, like $A \cap B$?

#### nickar1172

##### New member
Hi again,

I probably need some more information. Are you simply asked to write these concepts mathematically, like $A \cap B$?
Yes that is exactly what I am talking about

#### Jameson

Staff member
Yes that is exactly what I am talking about
Ok well we can use $A, A^c, B, B^c$ for referring to the sets and we can also use $\cup, \cap$. What do you get for the first one?

(by the way, $\cup$ means "or" and $\cap$ means "and")

#### nickar1172

##### New member
If I new I wouldn't be asking the question.....
Postulates for Probability - P(A) >= 0, P(S) = 1
Special Addition Rule (mutually exclusive) - If A ∩ B = ∅, then P(A ∪ B) = P(A) + P(B)
General Addition Rule - P(A ∪ B) = P(A) + P(B) – P(A ∩ B)
Probability and Odds (odds of A to B) - a / (a + b)
Conditional Probability - P(A | B) = P(A ∩ B) / P(B) provided that P(B) ≠ 0
General Multiplication Rule - P(A ∩ B) = P(A) . P(B | A)
Special Multiplication Rule(Independent events) - P(A ∩ B) = P(A) . P(B)
Multiplication Rules - if event B is independent of event A, then P(B | A) = P(A)

according to any of these rules how do you answer those question because I have NO IDEA how to

#### Jameson

Ok, (a) is $A^c \cap B^c$. Put into words this is "not A and not B". For (b), what is "A or B" in symbolic language? What is "A and B"?