JEE Main 2012 Mathematics question
Assuming the balls to be identical except for difference in colours, the number of ways in which one or more balls can be selected from 10 white, 9 green and 7 black balls is
Answer: (4)
Solution
Choose 0–10 white, 0–9 green, 0–7 black: selections, minus the empty one: 879, option (4).