statistics
posted by iris .
company A has 110 employed, company B has 750 employed and company C has 250 employed. Compute the probability that an employee selected at random comes from company A or B.

Size of set A = A = 110,
similarly B=750, C=250
Size of Ω, sample space, S = A+B+C=1110
Random selection from equiprobability sample would be
P(A or B)=P(A)+P(B)=(A+B)/S