Question 1126131
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According to the condition, for any single property the probability not selling it during a week is 100% - 40% = 1 - 0.4 = 0.6.


The probability not selling any one of 13 properties during a week is  {{{0.6^13}}}.


The probability to sell at least 1 property in one week is the <U>COMPLEMENT</U> to it  


    1 - {{{0.6^13}}} = 0.9987 = 99.87%.     <U>ANSWER</U>
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Solved.