## Probablity question, IB math HL

Discussions for the Core part of the syllabus. Algebra, Functions and equations, Circular functions and trigonometry, Vectors, Statistics and probability, Calculus. IB Maths HL Revision Notes

### Probablity question, IB math HL

Probability- IB Mathematics HL – IB maths HL

How can we find the probability $P(A\cap B’)$ if A and B are two events such that $P(A)=0.5$, $P(B)=0.3$ and $P(A \cup B)=0.7$?

Thanks
elizabeth

Posts: 0
Joined: Mon Jan 28, 2013 8:09 pm

### Re: Probablity question, IB math HL

Probability - IB Mathematics HL – IB maths HL

We know that

$P(A \cup B)=P(A)+P(B)-P(A \cap B) \Rightarrow$

$P(A \cap B)=0.5+0.3-0.7=0.1$

Finally, we have

$P(A \cap B’)=P(A)-P(A \cap B) =0.5-0.1=0.4$

Hope these help!!
miranda

Posts: 268
Joined: Mon Jan 28, 2013 8:03 pm

### Re: Probablity question, IB math HL

Thank you!
elizabeth

Posts: 0
Joined: Mon Jan 28, 2013 8:09 pm

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