document.write( "Question 473709: If we roll 4 dice once, what is the chance the sum will be 12? \n" ); document.write( "
Algebra.Com's Answer #324952 by Edwin McCravy(20086) You can put this solution on YOUR website! If we roll 4 dice once, what is the chance the sum will be 12? \n" ); document.write( " \r\n" ); document.write( "The other tutor didn't even start to solve your problem. Counting\r\n" ); document.write( "the number of ways to have sum 12 is NO EASY TASK! And the denominator\r\n" ); document.write( "is not 24 at all. It's 64.\r\n" ); document.write( "\r\n" ); document.write( "There are these 11 sets of ways disregrading order that the 4\r\n" ); document.write( "dice can have sum 12. However the dice are different so we must \r\n" ); document.write( "rearrange each of these in all possible distinguishable arrangements:\r\n" ); document.write( "\r\n" ); document.write( "1. 1 1 4 6 <-- 4!/2! = 12 distinguishable arrangements \r\n" ); document.write( "2. 1 1 5 5 <-- 4!/(2!2!) = 6 distinguishable arrangements\r\n" ); document.write( "3. 1 2 3 6 <-- 4! = 24 distinguishable arrangements\r\n" ); document.write( "4. 1 2 4 5 <-- 4! = 24 distinguishable arrangements\r\n" ); document.write( "5. 1 3 3 5 <-- 4!/2! = 12 distinguishable arrangements\r\n" ); document.write( "6. 1 3 4 4 <-- 4!/2! = 12 distinguishable arrangements\r\n" ); document.write( "7. 2 2 2 6 <-- 4!/3! = 4 distinguishable arrangements\r\n" ); document.write( "8. 2 2 3 5 <-- 4!/2! = 12 distinguishable arrangements\r\n" ); document.write( "9. 2 2 4 4 <-- 4!/(2!2!) = 6 distinguishable arrangements\r\n" ); document.write( "10. 2 3 3 4 <-- 4!/2! = 12 distinguishable arrangements\r\n" ); document.write( "11. 3 3 3 3 <-- 4!/4! = 1 distinguishable arrangement\r\n" ); document.write( "\r\n" ); document.write( "The numerator of the desired probability is\r\n" ); document.write( "\r\n" ); document.write( "12+6+24+24+12+12+4+12+6+12+1 = 125\r\n" ); document.write( "\r\n" ); document.write( "The denominator is 64 since each die can land 6 ways:\r\n" ); document.write( "\r\n" ); document.write( "So the answer is\n" ); document.write( " |