Solution Found!
(a) In 3.66b, find the probability that a current flows
Chapter 3, Problem 16STE(choose chapter or problem)
Problem 16STE
(a) In Problem 3.66b, find the probability that a current flows from A to B, by conditioning on whether relay 1 closes.
(b) Find the conditional probability that relay 3 is closed given that a current flows from A to B.
Questions & Answers
QUESTION:
Problem 16STE
(a) In Problem 3.66b, find the probability that a current flows from A to B, by conditioning on whether relay 1 closes.
(b) Find the conditional probability that relay 3 is closed given that a current flows from A to B.
ANSWER:
Step 1 of 2
(a)
We are asked to find the probability that a current flows from to by conditioning on whether relay 1 closes.
Let be the event the relay is closed (so that current can flow through that connection) and let be the current flows between and
If relay 1 is closed then the event current flows is
If on the other hand relay 1 is open the event current flows is
Thus the probability that current flow is using total probability rule,
Since all relays are independent, we can write using addition rule of probability
By independence, each of term in the above can be expanded in terms of products of using these two results we find