Question

Find P(A/B), in S = {10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80), A = 40 or less in S and B = even in S. Use fraction form for the probability​

Answer 1

P(A|B) = 1/2

Explanation:

Sample space for B = {10, 20, 30, 40, 50, 60, 70, 80}

where B is even

Total number of elements in sample space = 8

P(A|B) = Probability of a number being 40 or less from the sample space of 8

Sample space for A|B = {10, 20, 30, 40}

So out of a possible 8 elements in the sample space for B only 4 elements can be chosen for the sample space of A

So P(A|B) = 4/8 = 1/2