SOLUTION: Given that P(A or B) = 1/4, P(A) = 1/7, and P(A and B) = 1/8, find P(B)

Algebra ->  Probability-and-statistics -> SOLUTION: Given that P(A or B) = 1/4, P(A) = 1/7, and P(A and B) = 1/8, find P(B)      Log On


   

Question 1159974: Given that P(A or B) = 1/4, P(A) = 1/7, and P(A and B) = 1/8, find P(B)
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
P(A or B) = P(A) + P(B) - P(A and B)
     |    |  |   |  |   |     | 
    1/4   = 1/7  +  x   -    1/8

1%2F4+=+1%2F7+%2B+x+-+1%2F8 

Multiply through by LCD = 56

14+=+8+%2B+56x+-+7

14+=+1%2B56x

13=56x

13%2F56=x

Edwin