Question 1046976: You have 90 balls altogether. 20 of them are white, 25 are blue,
27 are red, and 18 are green. Now you will draw a ball one at a
time randomly until you've drawn any of the following: either 11
white, 9 blue, 3 red, or 14 green. What is the minimum number of
balls you have to draw until you are 100% sure that you've gotten
one of the previous combinations?
Answer by Edwin McCravy(20060)   (Show Source):
You can put this solution on YOUR website! You have 90 balls altogether. 20 of them are white, 25 are blue,
27 are red, and 18 are green. Now you will draw a ball one at a
time randomly until you've drawn any of the following: either 11
white, 9 blue, 3 red, or 14 green. What is the minimum number of
balls you have to draw until you are 100% sure that you've gotten
one of the previous combinations?
The most number of balls you could possibly have drawn and failed
is to have drawn 10 whites, 8 blues, 2 reds and 13 greens. That
case is possible when 10+8+2+13=33 balls are drawn. You would
necessarily have more than 10 whites or 8 blues or 2 reds or 13
greens in any other case of drawing 33 balls. That is to say,
any other case when 33 balls have been drawn will be a success.
But even in that extreme case, if you draw one more ball, you
must succeed.
Answer: 34 balls.
Edwin
|
|
|
