A person has 100 light bulbs whoso lifetimes are independent

A person has 100 light bulbs whoso lifetimes are independent exponentials with mean 5 hours. The bullbs are used one at a time, with a failed bulb being replaced immediately by a new one. Approximate the probability that there is still a working bulb after 525 hours. Suppose that it takes a random time, uniformly distributed over (0,0.5), to replace a fatted bulb. Approximate the probability that all bulbs have failed by time 550. A box contains 100 pieces of jewelry. Each piece is either a necklace or ring wah probabilities. The price of each ring is a continuous uniform random variable m the metered the price of each necklace is also a continuous uniform random vanable in the interval

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