A bag contains 20 balls. 8 balls are green, 7 are white and 5 are red. what is the minimum number of balls that must be picked up from the bag blindfolded (without replacing any of it) to be assured of picking at least one ball of each colour?
Answers
Minimum number of balls that must be “picked up from the bag blindfolded to be assured of picking at least one ball” of each colour is 16 balls.
Solution:
Given: A bag contains ‘20 balls’. “8 balls” are green, “7 are white and 5 are red”.
We have 5 red balls i.e. the least number of balls. Hence, the “probability of getting red balls” is lesser than the “probability of getting green and white balls”.
Now, we have 8 green balls and 7 white balls which means that to get green balls we have 8 chances and to get white balls we have 7 chances. Hence, if we pick 15 balls we there are chances to get 8 green balls and 7 white balls. If we pick one more ball i.e. 16h time, then there are chances to get red balls as we have 15 balls of other colors.
Hence, to get atleast one ball of each color, one has to pick 16 balls.