Question 214683
a)

Total number of marbles = 23 + 4 = 27 marbles



P(Green Marble) = (# of green marbles)/(# of marbles total) = 4/27 = 0.148



So the probability is 4/27 which is about a 14.8% chance


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b)


Since the selected marble from part a) is not replaced, the total number of marbles is now 27-1=26


P(Red Marble) = (# of red marbles)/(# of marbles total) = 23/26 = 0.885



So the probability is 23/27 which is about a 88.5% chance


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c)


To find the probability of NOT choosing green after four selections, you simply calculate the probability of choosing red 4 times in a row (without replacement). This works because there are only two choices in marble selection.



So the basic outline is


P(4 red) = P(red)*P(red with 1 less from total)*P(red with 2 less from total)*P(red with 3 less from total)



I'll let you take it from here. Let me know if you still need help.