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A manager of a pizza parlor (which operates 7 days a week) allows each of 3 employees to select 1 day off next week. Assuming the selection is done randomly and independently. What is the probability that all three select different days?
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First employee can select any of 7 days of a week;
second employee can select any of remaining 6 days of a week;
third employee can select any of remaining 5 days of a week.
In all, there are 7*6*5 possibilities to select different days.
The full set of possibilities is .
So, the answer is = = 0.612245.