My Math Forum a question about permutations

 Probability and Statistics Basic Probability and Statistics Math Forum

 March 9th, 2018, 01:11 PM #1 Newbie     Joined: Jun 2017 From: Iraq Posts: 4 Thanks: 0 a question about permutations Hi, There are 6 girls, 2 boys to be arranged in a row. How many ways N are there if The boys should be not together? please help
 March 9th, 2018, 03:18 PM #2 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,647 Thanks: 955 1 = girls, 2 = boys from 11111212 to 21211111 : 21 ways Or there is a total of 28 ways, of which the boys are together in 7.
 March 9th, 2018, 04:58 PM #3 Newbie     Joined: Jun 2017 From: Iraq Posts: 4 Thanks: 0 but the answer of lectures is 30240! the following solution is the full example with answer ...
 March 10th, 2018, 09:44 AM #4 Member   Joined: Jan 2016 From: Athens, OH Posts: 92 Thanks: 47 I interpret your problem as having 8 different people of which 6 are girls and 2 are boys. That is the set $\{b_1,b_2,g_1,g_2,g_3,g_4,g_5,g_6\}$. So the number of permutations of the set with the b's together is $7\cdot2\cdot6!$ and the complement then has $8!-14\cdot6!=42\cdot6!=30240$
 March 10th, 2018, 12:52 PM #5 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,647 Thanks: 955 ...and I took it as the 6 girls being identical sixtuplex and the boys identical twins!!

 Tags permutations, question

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post jasonbing Advanced Statistics 1 December 13th, 2011 08:42 PM LoveOneAnother Abstract Algebra 0 November 6th, 2010 07:05 PM r-soy Algebra 4 March 4th, 2010 10:08 AM r-soy Algebra 1 March 4th, 2010 03:35 AM EternalSummer247 Advanced Statistics 2 August 17th, 2007 06:03 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top