document.write( "Question 143040: A bag contains 15 billiard balls, numbers consecutively from 1 to 15. Six balls are selected at random. What is the probability that the sum of the numbers on the billiard balls will be odd? \n" ); document.write( "
Algebra.Com's Answer #104095 by edjones(8007) You can put this solution on YOUR website! 8 are odd, 7 are even. \n" ); document.write( "All the possible combinations are: \n" ); document.write( "8C6=28 [all odd] \n" ); document.write( "8C5 * 7C1 =56*7=392 [5 odd, 1 even] \n" ); document.write( "8C4 * 7C2 =70*21=1470 [4 odd, 2 even] \n" ); document.write( "8C3 * 7C3 =56*35=1960 [3 odd, 3 even] \n" ); document.write( "8C2 * 7C4 =28*35=980 [2 odd, 4 even] \n" ); document.write( "8C1 * 7C5 =8*21=168 [1 odd, 5 even] \n" ); document.write( "7C6=7 [all even] \n" ); document.write( ". \n" ); document.write( "Adding all these numbers we get 5005 possible combinations. \n" ); document.write( "Only those with an odd number of odd numbers give an odd result. \n" ); document.write( "They are: 392+1960+168=2520 \n" ); document.write( "2520/5005=72/143 or .503497 Probability that the sum of the numbers will be odd. \n" ); document.write( ". \n" ); document.write( "Ed\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |