P(R2)=? how does it come

[manish....@gmail.com]

Hi,

I have a question about what is happening in this video at 00:40:09 -

http://www.youtube.com/watch?v=uLn7gaxeC_A#t=2409s.

How does P(R2) comes as p(R2 intersection R1 or R2 interse tion B1). Pls explain.

Thanks!

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