3 Let B be an event of a sample space S Suppose 0 SolutionGi
3. Let B be an event of a sample space S. Suppose 0
Solution
Given that 0<P(B)<1 and 0<P(B\')<1
This implies that B is a subset of universal set and B\' also and both are not null sets
i.e. BUB\' = U and Bint B equals phi.
B and B\' are mutually exclusive and exhaustive events with prob >0 but <1
Consider any set A in U.
A can also be written as A\\B UA\\B\'
Hence P(A) = P(A\\B)+P(A\\B\')-P(A\\B int A\\B\')
Or P(A) <P(A\\B)+P(A\\B\')
Hence proved.
