we have numbered balls in a bag from 1 to 10. We put our hand and take one. Let the number of X be the first number of the ball. Replace the ball into the bag again and takes another ball at random. Let the number of Y the number of the second ball.(adsbygoogle = window.adsbygoogle || []).push({});

IF Z =max{X, Y}.

we want to find P(Z=9)

First of all i used the type (n+k-1)c(k) because we replace the ball again and i found this (8)c(55) but its says tha its not correct answer, what i am doing wrong?

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# Numbered balls and replacement

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