Balls in the bag

(11 10 8) - 1 = 879 The no. of ways of selecting one or more balls of white color is 11 (1 way to select 1 white ball, 1 way to select 2 white balls and so on.. also, one way to select NO white balls). The same goes for green and black balls. One is subtracted from this product as it corresponds to selecting no balls at all.

$(10+1).(9+1).(7+1)-1$ .. because for $n$ identical balls of same colour ,you can select them in $n+1$ ways or you can select none from them... By calculating we get the answer as $\boxed{879}$ . This is because if we select none then we will have to subtract $1$ . from the total ways.

One can choose 1 white ball, 2 white balls, 3 white balls...10 white balls or no white balls. So that's 11 ways. Since there are 9 green and 7 black balls, the total number of ways are 11 10 8= 880 ways. But you have to minus 1 if no balls are picked.