# Thread: Venn diagram and Probability

1. ## Venn diagram and Probability

Hi I am quite bad at IB Maths Probablitiy, if you guys could help that would be much appreciated.

Events A and B are such that P(A) = 0.3, P(B) = 0.6 and P(A∪B) = 0.7

The values q, r, s and t represent probabilities.

(a) Write down the value of t.
(b) Show that r = 0.2.
(c) Write down the value of q and of s.
(d) Write down P(B').
(e) Find P(A|B')

Cheers!

2. ## Re: Venn diagram and Probability

Originally Posted by tchoxobey
Hi I am quite bad at IB Maths Probablitiy, if you guys could help that would be much appreciated.
Events A and B are such that P(A) = 0.3, P(B) = 0.6 and P(A∪B) = 0.7
The values q, r, s and t represent probabilities.
(a) Write down the value of t.
(b) Show that r = 0.2.
(c) Write down the value of q and of s.
(d) Write down P(B').
(e) Find P(A|B')
You need to understand that this is not a homework service.
You are expected to show some efforts.

Hints: $\displaystyle q+r+x+t=1$
& $\displaystyle \mathcal{P}(A\cup B)=\mathcal{P}(A)+\mathcal{P}(B)-\mathcal{P}(A\cap B)~.$