If P(A) = 0.45, P(B) = 0.7, and P(A and B) = 0.65, then find P(A or B).

Please help!

Guest Sep 11, 2020

#1**0 **

First, do 0.7*0=0.315? This is obviously not 'and' probability, but I don't know if I am missing something so I will do it the way I would without any mistakes in the problem...

P(A U B) = 0.45 + 0.7 – 0.65 = 0.5= 1/2

Also, U is the 'or' sign in probability.

This is P(A)+P(B)-P(A and B), the formula for 'or' probabilities.

Your answer is **0.5**

Pangolin14 Sep 11, 2020