TT GWD-21-37一道未讨论过的概率题，望高手不吝赐教:P

古韵 · 发表于 2009-4-5 19:11:00

请教各路牛人:

本人在做GWD31套时遇到题号为：GWD-21-37的概率题，困惑当中，望高手不吝赐教

Q37:

A gumball dispenser has 24 gumballs, 12 white and 12 black, which are dispensed at random. If the first 3 gumballs dispensed are black, what is the probability that the next gumball dispensed will be black?

A.1/2 B.1/3 C.1/4 D.3/7 E.3/8

Key: D

vivien_hu · 发表于 2009-4-5 19:21:00

取了三次后，还剩下21个

黑色的还剩下9

9/21

古韵 · 发表于 2009-4-5 20:10:00

谢谢

阿彻 · 发表于 2009-8-3 11:37:00

TT GWD-21-37一道未讨论过的概率题，望高手不吝赐教:P

TT GWD-21-37一道未讨论过的概率题，望高手不吝赐教:P

所属分类: GMAT考试

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