A box contains 100 balls. Some of them are white, some red, some green, some blue and some black. What's the smallest number of balls we have to take so the next time we can be sure of getting two balls of the same color ?
Answers
Answered by
3
Obviously, other people have given correct solutions.
I have a slightly different way of expressing it which I think is more complete.
The largest number of balls OF A PARTICULAR COLOUR you can have, without having 15, is either 14, or the total number of balls in that colour (which ever is larger).
Therefore, the largest number of balls OF ANY COLOUR you can select WITHOUT having 15 of any one colour is: 14 red, 14 blue, 14 green, 10 white, 12 yellow and 12 black (i.e. the sum of the largest number of each balls of each colour).
Therefore if you have greater than 76 balls, you must have at least 15 balls of at least 1 colour.
Similar questions