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There are six balls in a black sack. Among those six are [#permalink]
27 Jun 2003, 00:35
0% (00:00) correct
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There are six balls in a black sack. Among those six are black ball and white one. Three balls are taken at random without repetition. What is the probability that the white ball IS taken, but the black one IS NOT?
F=1C1 (the whithe ball is taken)*5C4 (the black is not)
Should be 1c1 * 4c2 / 6c3.
We have one way to choose a white ball we want to know how many ways we can pair it with two of the four other non-black balls. This divided by 6c3 gives you 3/10 or .30.
AkamaiBrah Former Senior Instructor, Manhattan GMAT and VeritasPrep Vice President, Midtown NYC Investment Bank, Structured Finance IT MFE, Haas School of Business, UC Berkeley, Class of 2005 MBA, Anderson School of Management, UCLA, Class of 1993