The Proprietor of Cunningham's Hardware Store Has Decided to Install

Short Answer

The proprietor of Cunningham's Hardware Store has decided to install floodlights on the premises as a measure against vandalism and theft.
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If the probability is 0.01 that a certain brand of floodlight will burn out within a year, find the minimum number of floodlights that must be installed to ensure that the probability that at least one of them will remain functional within the year is at least 0.9999. (Assume that the floodlights operate independently.)
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The probability is __________.