If a box has 5 white balls and 5 black balls the chance of picking 2 black balls is ?

Question

Probability rules if the events are non independent 

Answer 1

When you choose the first ball, there are 10 balls and 5 are black.  So P(black)= 5/10.

 

When you choose the second ball, there are 9 balls and 4 are black.  So P(black) = 4/9.

 

This is really P(black AND black). Andeans multiply....(5/10)*(4/9)=?