1. The problem statement, all variables and given/known data Consider a system of water flowing through valves from A to B as shown in the diagram. Valves 1, 2, and 3 operate independently, and each correctly opens on signal with probability 0.8. Find the probability distribution / probability mass function for Y, the number of open paths from A to B after the signal is given (Note that Y can take on the values 0, 1, and 2.) http://www.geocities.com/asdfasdf23135/sta1.JPG 2. Relevant equations Probability mass function just means finding the probabilities of all possible outcomes 3. The attempt at a solution I don't understand the question itself so I can't get anywhere (coloured in red). Does anyone actually understand what is going on in this scenario? I would truly appreciate if somebody can explain it to me.