shrive555 wrote:
The probability that event A occurs is 0.4, and the probability that events A and B both occur is 0.25. If the probability that either event A or event B occurs is 0.6, what is the probability that event B will occur?
0.05
0.15
0.45
0.50
0.55
P(A) = .40
P(A and B) = P(A) * P(B) = .25 ----1
P(A or B) = P (A) + P(B) = .60 -----2
Both 1 & 2 give different results.
1 => P(B) = .25/P(A) = 0.62
2=> P(B) = .60 - .40 = .20
whats going wrong ...i don;t know![:roll:]( "Rolling Eyes")
0.05
0.15
0.45
0.50
0.55
P(A) = .40
P(A and B) = P(A) * P(B) = .25 ----1
P(A or B) = P (A) + P(B) = .60 -----2
Both 1 & 2 give different results.
1 => P(B) = .25/P(A) = 0.62
2=> P(B) = .60 - .40 = .20
whats going wrong ...i don;t know
The only correction you need is to minus...
P(A or B) = P (A) + P(B) - P(A) * P(B) =
or, 0.60 = 0.4 +p(B) - 0.25
so, p(B) = 0.45 (C)
we all make mistake....don't worry about it...
