17. A testing laboratory has facilities to simultaneously life test 5 components. The lab tested a sample of 10 components from a common exponential distribution by initially putting 5 on test and then replacing any failed component by one still waiting to be tested. The test was designed to end either at 200 hours or when all 10 components had failed. If there were a total of 9 failures occurring at times 15, 28.2, 46, 62.2, 76, 86, 128, 153, 197, what is the maximum likelihood estimate of the mean life of a component?