document.write( "Question 1170216: An urn contains 4 red balls, 2 green balls, and 4 blue balls. If 10 balls are
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Algebra.Com's Answer #795121 by Edwin McCravy(20063)\"\" \"About 
You can put this solution on YOUR website!
An urn contains 4 red balls, 2 green balls, and 4 blue balls. If 10 balls are
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document.write( "The procedure is to make selection 1, then put it back, then make selection 2,\r\n" );
document.write( "then put it back, then selection 3, then put it back, then..., selection 10,\r\n" );
document.write( "then put it back.\r\n" );
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document.write( "There are 4+2+4=10 balls and we are selecting 10 balls.\r\n" );
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document.write( "There are C(10,4) selections where the 4 reds could occur.\r\n" );
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document.write( "Each selection could have been a red ball in 4 ways. That's 44 ways.\r\n" );
document.write( "Each of the other 6 balls could have been a non-red ball in 6 ways.  That's 66 ways.  \r\n" );
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document.write( "So the numerator of the probability is \"C%2810%2C4%29%2A4%5E4%2A6%5E6\" = 2508226560\r\n" );
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document.write( "The denominator is gotten by:\r\n" );
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document.write( "(10 ways for the 1st selection) times (10 ways for the 2nd selection) times...\r\n" );
document.write( "all the way to 10, so the denominator is 1010. = 10000000000\r\n" );
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document.write( "So the answer is 2508226560/10000000000 which by dividing numerator and denominator by 5120,\r\n" );
document.write( "reduces to 489888/1953125 or about 0.250822656 or rounded off, about 0.25, or\r\n" );
document.write( "about a fourth of the time. \r\n" );
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What is the probability that exactly 2 green balls will be selected?
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document.write( "That's done the same way, only the numbers are different.  The denominator will\r\n" );
document.write( "be the same.  You do it!  If you have trouble, tell me in the note below.\r\n" );
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document.write( "Edwin
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