document.write( "Question 1067726: In how many ways can a group of 4 students and a teacher be chosen from 12 students and 4 teachers? \n" ); document.write( "
Algebra.Com's Answer #682859 by Theo(13342)![]() ![]() You can put this solution on YOUR website! you've got 12 students and 4 teachers. \n" ); document.write( "you want to choose 4 students and 1 teacher.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the students can be chosen in c(12,4) ways. \n" ); document.write( "the teacher can be chosen in c(4,1) ways. \n" ); document.write( "they can both be chosen in c(12,4) * c(4,1) ways.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c(12,4) = 12! / (4! * 8!) = 495 \n" ); document.write( "c(4,1) = 4! / (1! * 3!) = 4 \n" ); document.write( "495 * 4 = 1980\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "they can both be chosen in 1980 ways.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "to see how it works, make it real simple. \n" ); document.write( "assume 3 students and 2 teacher. \n" ); document.write( "you want 2 students and 1 teacher.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "per the formula, this can ocurr in c(3,2) * c(2,1) ways which is equal to 6 ways.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "let the students be a,b,c \n" ); document.write( "let the teachers be 1,2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you want 2 students and 1 teacher.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the number of ways will be:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a,b,1 \n" ); document.write( "a,b,2 \n" ); document.write( "a,c,1 \n" ); document.write( "a,c,2 \n" ); document.write( "b,c,1 \n" ); document.write( "b,c,2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |