Given, Eand F are event such that,
P( E )= 1 4 P( F )= 1 2 P( E and F )= 1 8
(i)
The probability P( E or F )is,
P( E or F )=P( E )+P( F )−P( E and F ) = 1 4 + 1 2 − 1 8 = 2+4−1 8 = 5 8
(ii)
The probability P( not E and not F ) is,
P( E or F )=P( E∪F ) = 5 8 P( not E and not F )=P( E ′ ∩ F ′ ) =P ( E∪F ) ′
Further simplify.
P( not E and not F )=P ( E∪F ) ′ =1−P( E∪F ) =1− 5 8 = 3 8
Thus, P( not E and not F ) is 3 8 .
If E and F are events such that P(E) =, P(F) = and P(E and F) =, find:(i) P(E or F), (ii) P(not E and not F).