Acompany has three different sites: site 1, site 2 and site 3. at site 1 70% of the employees are bu alum, at site 2 20% of the employees are bu alum, at site 3 10% are bu alum. there are an equal number of employees at each of the three sites. if an employee is randomly selected for employee of the month what is the probability that they are a bu alum