GMAT Problem Solving (PS) | Re: There are 18 balls in a jar. You take out 3 blue balls without putting

There are 18 balls in total and 3 are removed without replacement . So there are total of 18-3=15 balls remaining. the probability of drawing the remaining blue balls is 1/5 and lets says there are n balls remaining out of a total of 15 balls. So n/15=1/5 therefore n=3+ 3 which were removed in the beginning =6

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