The GATE Grind

GATE 2023 PI – Question 52

Quality and Reliability · Reliability and Maintenance · 2 marks · Numerical answer

The shown system has seven components with reliabilities R_A = 0.96, R_B = 0.92, R_C = 0.94, R_D = 0.89, R_E = 0.95, R_F = 0.88 and R_G = 0.90. Find system reliability to two decimals.

Diagram for GATE 2023 PI question 52

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 0.80 to 0.84

Explanation

Assume independent failures. First parallel block has reliability $1-(1-R_A)(1-R_B)=0.9968$. The last block has E,F in series parallel to G, so reliability is $1-(1-0.95\times0.88)(1-0.90)=0.9836$. These blocks are in series with C and D: $R=0.9968(0.94)(0.89)(0.9836)=0.8202$. Rounded: **0.82**.

More Reliability and Maintenance questions

All Reliability and Maintenance questions →