(2) The initial design of a system involves 3 subsystems. The constituent reliabilities of the subsystems are R_1=0.85, R_2=0.6 and R_3=0.73. Parallel redundancy is to be used to improve the initial design so that it meets the reliability goal of Rg=0.9. Each subsystem is assumed to cost 1 unit, and the total cost budget is 17 units. Apply the greedy algorithm to achieve the target reliability. Explain fully (in words!) all your steps.