There are 15 tennis balls in a box, of which 9 havenot
Chapter 3, Problem 3.29(choose chapter or problem)
There are 15 tennis balls in a box, of which 9 havenot previously been used. Three of the balls arerandomly chosen, played with, and then returnedto the box. Later, another 3 balls are randomlychosen from the box. Find the probability thatnone of these balls has ever been used.
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