document.write( "Question 315863: A bag contains 4 red and 2 green jelly beans, the second bag contains 2 red and 3 green jelly beans. A bag is selected at random and a jelly bean is randomly taken from it. The jelly bean is red.\r
\n" ); document.write( "\n" ); document.write( "What is the probability that it came from the first bag?\r
\n" ); document.write( "\n" ); document.write( "(Bayes's theorem)
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Algebra.Com's Answer #225987 by stanbon(75887)\"\" \"About 
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A bag contains 4 red and 2 green jelly beans, the second bag contains 2 red and 3 green jelly beans. A bag is selected at random and a jelly bean is randomly taken from it. The jelly bean is red.
\n" ); document.write( "What is the probability that it came from the first bag?
\n" ); document.write( "---------------
\n" ); document.write( "P(1st|red) = P(1st and red)/P(red)
\n" ); document.write( "= [P(red|1st)*P(1st)]/[P(red and 1st + P(red and 2nd)]
\n" ); document.write( "= [(4/6)*(1/2)]/[(4/6)*(1/2) + (2/5)(1/2)]
\n" ); document.write( "= [(1/3)/[(1/3)+(1/5)]
\n" ); document.write( "= (1/3)/(8/15)
\n" ); document.write( "= 5/8
\n" ); document.write( "==============
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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