Question 928550
 <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi
       X      Y      Tot

A    24     31      55

B    13     66      79

Tot  37     97     134
.......
P(A or B) = P(A) + P(B) - P(A and B)
 P(X or A) = 37/134 + 55/134 - 24/134 = 68/134 = 34/67
.......
P(A|B) = P(A and B)/P(B)
P(X|A) = {{{(24/134)/(55/134)}}} = 24/55
Good  Work.