SOLUTION: From a class of girls and boys, the probability that one student chosen at random will be a girl is 1/3. If four boys leave the class, the probability that a student chosen at ran
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Question 76181This question is from textbook
: From a class of girls and boys, the probability that one student chosen at random will be a girl is 1/3. If four boys leave the class, the probability that a student chosen at random will be a girl is 2/5. How many boys and girls are there in the class before the four boys leave? This question is from textbook
You can put this solution on YOUR website! From a class of girls and boys, the probability that one student chosen at random will be a girl is 1/3. If four boys leave the class, the probability that a student chosen at random will be a girl is 2/5. How many boys and girls are there in the class before the four boys leave?
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Let "b" be # of boys; Let "g" be # of girls.
EQUATIONS:
g/b=1/3
g/(b-4)=2/5
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b-3g=0
2b-8=5g
or
2b-5g=8
And mulriplying the 1st equation by 2 you get:
2b-6g=0
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Subtract one from the other to get:
g=8 (number of girls)
Substitute to get
b=3g=24 (number of boys)
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Cheers,
Stan H.
Stan H.
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