Solution:
We can select 0 or more balls out of 10 white balls in 11 ways. [select 0 or 1 or 2 or 10 white balls.]
Thus, the number of ways of making a selection of 0 or more balls
Assuming the balls to be identical except for difference of colours the number of ways in which one or more ball can be selected from 10 white, 9 green and 7 black balls is:
Assuming the balls to be identical except for difference of colours the number of ways in which one or more ball can be selected from white, green and black balls is:
