Question: A zircon semiconductor is critical to the operation of a superconductor and must be immediately replaced upon failure. Its expected lifetime is 100 hours, and its standard deviation is 34 hours. If 22 of these semiconductors are available, approximate the probability that the superconductor can operate for the next 2000 hours. (That is, approximate the probability that the sum of the 22 lifetimes exceeds 2000.)