[" A signal which can be green or red with "],[" probability "(4)/(5)&(1)/(5)" respectively,is received by "],[" station A and then transmitted to station B."],[" The probability of each station receiving the "],[" signal correctly is "(3)/(4)" .If the signal received at "],[" station B is green,then the probability that the "],[" original signal was green is "],[" () "(6)/(7)],[(20)/(23)],[(9)/(20)]