Question

I have prepared 3 computers to receive a transaction. If my first computer fails, one of the two spares can be immediately switched online. After the second computer fails, the

last computer can be immediately switched online. We are told that the probability of a failure during any transaction is 10 and that the transactions can be considered to be independent events. a) What is the average number of transactions before all computers have failed? b) What is the variance of the number of transactions before all computers have failed?

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