The company can choose to buy a back up machine for step C for an additional $30,000. The back up would also have a reliability of 0.905, just like...

The company can choose to buy a back up machine for step C for an additional $30,000. The back up would also have a reliability of 0.905, just like the one that is presently used. If it is used what will the new reliability  be? 

Step A: 0.989 

Step B: 0.977

Step C: 0.905

Please show the formula used and how to get the answer.

SYSTEM RELIABILITY INCLUDING COMPONENTS INPARALLELAugust 07, 2016Question:The company can choose to buy a backup machine for step C for an additional$30,000. The backup would also have a...