ehp1098
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Suzan sees a bag of marbles, she grabs a handful at random. She has seen a bag containing three red marbles, two green ones, three white ones, and three purple ones. She grabs eight of them. Find the probability of the following event, expressing it as a fraction in lowest terms. She has at least one green one.

Respuesta :

The answer to this question would be: 52/55

In this question, Suzan is taking 8 marble from a bag containing 3 red marbles, 2 green ones, 3 white ones, and 3 purple ones. The total marble in the bag should be: 3+2+3+3= 11. The question is how much the probability to get at least one green one. This means the opposite probability of no green at all. The green marble is 2 of 11 so the chance to not getting green would be 9/11 for the first attempt and then 8/10 for the second.
Then the probability for no green marble would be: 
(9!/9-8!)/ 11!/8!= 9*8*7*6*5*4*3*2/ 11*10*9*8*7*6*5*4=  3*2/ 11*10= 3/55

The probability for at least one green one: 1-3/55= 52/55

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