
Probability Question
Could use some help solving this problem:
A company has 20 computers total. Out of these 20 computers, 9 run web servers and 12 host databases. In addition, 8 machines offer file sharing. Note: a particular machine can offer multiple service. In fact, 2 computers proved web services, databases, and file sharing concurrently. Given this information a) If a computer is selected at random, what is the probability that it hosts a database? b) Out of the 12 machines that host databases, one fourth of them offer file sharing. How many of the database machines don't provide sharing? c) Suppose a web server is selected at random. The probability that this computer provides file sharing is 1/3. If a file sharing machine is chosen randomly, what is the probability that it is also a web server? d) Out of the computers that run databases, 5 also offer web services. If a database server is selected at random, what is the probability that it does not offer any other services?

Re: Probability Question
Hey Mary3789.
Hint for a) Convert the information in your question to probabilities. As an example P(Web server) = # computers running web servers / # computers total = 9/20.
Do a similar thing for other pieces of information to obtain probabilities.

Re: Probability Question
You might want to create a chart of some sort to keep track of the different types of services and the numbers of computers offering them. Possibly draw twenty boxes and write in the services that each provides as you figure it out. For example, you are given that 2 computers offer all three services, so two of your computers should have all three. Then, there are 12 computers hosting a database, so there are 10 computers that are not among those two that are either not offering file sharing or are not web servers (or not either of those). Do this for each category. However you choose to visually represent the data, eventually, you will have enough information to follow chiro's advice and turn it into probabilities.