MasterPhil
Sachin Patel
Hi,
In one of the GMAT preparation notes, the following was stated :-
1) "E or F" is the set of outcomes in E or F or both, that is E U F
2) P(E or F) = P(E) + P(F) - P( E and F)
However i don't understand why the formula is deducting the probability of E & F because if they deduct that then the statement "both" in item 1 will become untrue.
If E or F = E or F or both, then how can they deduct the "both" from the summation of E + F?
I think the correct formula should be E or F = P(E) + P(F)
In one of the GMAT preparation notes, the following was stated :-
1) "E or F" is the set of outcomes in E or F or both, that is E U F
2) P(E or F) = P(E) + P(F) - P( E and F)
However i don't understand why the formula is deducting the probability of E & F because if they deduct that then the statement "both" in item 1 will become untrue.
If E or F = E or F or both, then how can they deduct the "both" from the summation of E + F?
I think the correct formula should be E or F = P(E) + P(F)