Solutions to Probability Puzzle: Find 3 Emergency Trained Staff

[statsluke]

Any possible solutions to the following probability puzzler? Cheers

A site with a rotating workforce provides emergency response training for some regular members of staff. In an emergency they are called into the emergency team. On the site 20% have emergency training. I want to find 3 emergency trained staff, and the contact list is out of date. What is the probability of getting 3 emergency trained staff after 3 phone calls. What is the probability of getting 2 after 3 calls?

 

[honestrosewater]

You don't even know it there are 3 emergency-trained staff. What if there's only 5 staff total? How many people are there at one time? How many of them are emergency-trained?
You said only the emergency-trained go on a call, so the question doesn't really make sense. Or do you just mean you're calling the place and want to know if the person who answers the phone is emergency-trained?