A control circuit contains four identical relays that operate independently
MATHEMATICS · Subjective · AP · AP Statistics · Probability Random Variables Distributions · Probability Random Variables Distributions
Problem
A control circuit contains four identical relays that operate independently. Each relay closes when required with probability 0.9.
(i) Calculate the probability that at least three of the four relays close.
(ii) Two such control circuits are connected in series; the overall system functions only if both circuits function. Find the probability that the overall system functions.
(iii) If instead the two circuits are connected in parallel so that the overall system functions if at least one of the two circuits functions, find the probability that the overall system functions.