Question

p(a) = 0.60, p(b) = 0.20, and p(a and b) = 0.15 what is p(a or b) choices: A. 0.12, B. 0.65, C. 0.40, or D. 0.80 (Note- This is on AP3X)

Answer 1

Answer:

$P(a\ or\ b) = 0.65$

Step-by-step explanation:

Given

P(a) = 0.60

P(b) = 0.20

P(a and b) = 0.15

Required

Determine P(a or b)

In probability;

$P(a\ and\ b) = P(a) + P(b) - P(a\ or\ b)$

Substitute values for P(a and b), P(a) and P(b)

$0.15 = 0.60 + 0.20 - P(a\ or\ b)$

Collect Like Terms

$P(a\ or\ b) = 0.60 + 0.20 - 0.15$

$P(a\ or\ b) = 0.65$

Hence, option B answers the question