SOLUTION: Help! If P(A or B) = 0.9, P(A) = 0.7 and P(B) = 0.5, determine P(A and B). Thanks! Melissa

Algebra ->  Probability-and-statistics -> SOLUTION: Help! If P(A or B) = 0.9, P(A) = 0.7 and P(B) = 0.5, determine P(A and B). Thanks! Melissa      Log On


   

Question 404542: Help!
If P(A or B) = 0.9, P(A) = 0.7 and P(B) = 0.5, determine P(A and B).
Thanks!
Melissa
Answer by sudhanshu_kmr(1152) About Me  (Show Source):
You can put this solution on YOUR website!

P(A U B) = P(A) + P(B) - P(A n B)
using this formula...
=> 0.9 = 0.7 + 0.5 - P(A n B)
=> P(A n B) = 1.2 - 0.9 = 0.3

SO, P( A AND B) = 0.3