saafiin wrote:Q: In a certain bag there are 12 identical blue balls, y identical yellow balls and no other ball. One ball will randomly removed. If the probability is less than 2/3 that the removed ball will be blue, then what is the least number of balls that must be in the bag?
please need help...unable to solve...
i changed the text to something that makes sense with the given answer choices.
the problem wants the least
number, so, try out the choices starting with the smallest one.
if there are (a) 17 balls -- 12 blue and 5 yellow -- then the probability of getting a blue one is 12/17, which is greater than 2/3. no good.
if there are (b) 18 balls -- 12 blue and 6 yellow -- then the probability of getting a blue one is 12/18, which is equal to 2/3. no good.
if there are (c) 19 balls -- 12 blue and 7 yellow -- then the probability of getting a blue one is 12/19, which is less than 2/3.