document.write( "Question 1067720: A bag contains two red beads and two green beads. You reach into
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Algebra.Com's Answer #682860 by Edwin McCravy(20056)\"\" \"About 
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A bag contains two red beads and two green beads. You reach into
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document.write( "The only way to succeed is to replace both green beads.\r\n" );
document.write( "There are three ways to do that:\r\n" );
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document.write( "Case 1.  Pull out R,G,G in that order\r\n" );
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document.write( "You begin with the bag containing RRGG.\r\n" );
document.write( "You draw a red one with probability 2/4 or 1/2.\r\n" );
document.write( "You replace it with another red one, then the bag still contains RRGG.\r\n" );
document.write( "You then draw a green one with probability 2/4 or 1/2.\r\n" );
document.write( "You replace it with a red one, then the bag contains RRRG.\r\n" );
document.write( "You draw the green one with probability 1/4.\r\n" );
document.write( "You then replace it with a red one, then the bag contains RRRR.\r\n" );
document.write( "So Case 1 happens with probability (1/2)(1/2)(1/4) = 1/16.\r\n" );
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document.write( "Case 2.  Pull out G,R,G in that order\r\n" );
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document.write( "You begin with the bag containing RRGG.\r\n" );
document.write( "You draw a green one with probability 2/4 or 1/2.\r\n" );
document.write( "You replace it with a red one, then the bag contains RRRG.\r\n" );
document.write( "You then draw a red one with probability 3/4.\r\n" );
document.write( "You replace it with another red one, then the bag still contains RRRG.\r\n" );
document.write( "You draw the green one with probability 1/4.\r\n" );
document.write( "You then replace it with a red one, then the bag contains RRRR.\r\n" );
document.write( "So Case 2 happens with probability (1/2)(3/4)(1/4) = 3/32.\r\n" );
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document.write( "Case 3.  Pull out G,G,R in that order\r\n" );
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document.write( "You begin with the bag containing RRGG.\r\n" );
document.write( "You draw a green one with probability 2/4 or 1/2.\r\n" );
document.write( "You replace it with a red one, then the bag contains RRRG.\r\n" );
document.write( "You then draw the green with probability 1/4.\r\n" );
document.write( "You replace it with a red one, then the bag contains RRRR.\r\n" );
document.write( "You draw a red one with probability 1 (certainty).\r\n" );
document.write( "You then replace it with a red one, then the bag still contains RRRR.\r\n" );
document.write( "So Case 2 happens with probability (1/2)(1/4)(1) = 1/8.\r\n" );
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document.write( "So the probability is 1/16 + 3/32 + 1/8 = 2/32 + 3/32 + 4/32 = 9/32\r\n" );
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document.write( "Edwin
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