Part A and B

Given a system which has three identical components, with 2 of those components in cold standby, as depicted in the figure. Assuming the failure rate is 1 failure per four months, what is the system reliability over 9 months? RS=0.50 RS=0.33 RS=0.61 RS=0.74 Suppose you had a system which has two subsystems in series. Further, subsystem A is composed of three identical components, Ai, with two components in cold standby. Subsystem B is composed of two identical components, Bi, in hot standby. The system can be depicted as, If the MTBF for each component in subsystem A is 30 hours (A1=A2=A3=30 hours), and the MTBF for each component in subsystem B is 45 hours (B1=B2= 45 hours), then what is the total MTBF for the system? MTBFSS=42.8 hours MTBFS=28.8 hours MTBFSS=38.6 hours MTBFsS=35.5 hours