3.1 Determine the reliability of the system below, given the following individual reliabilities.

Forty hydro generators were subjected to 10 000 hours of accelerated testing. Out of the forty generators, six (6) failed during the test in the following hours: one failed at 6600; two failed at 8800,three failed at 9000 hours and 1 failed at 9900 hours.

3.2.1 Calculate the percentage of failures, FR(%) (1.5) 3.2.2 Calculate the number of failures per unit hour, FR(N) (3) 3.2.3 Determine the mean time between failures (MTBF) for the generators. (1.5)