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