5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
Permutation and combination
This topic has expert replies
there are 5 teachers , 4 girls students ,6 boys students . 5 teachers are required to sit in the first row ,4 girls students are required to sit in the second row , 6 boys students are requires to sit in the last row . In how many ways the sitting arrangement can be made ??
GMAT/MBA Expert
-
Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
5 teachers can be arranged among themselves in 5! = 120 waysabcd1111 wrote:there are 5 teachers , 4 girls students ,6 boys students . 5 teachers are required to sit in the first row ,4 girls students are required to sit in the second row , 6 boys students are requires to sit in the last row . In how many ways the sitting arrangement can be made ??
4 girls can be arranged among themselves in 4! = 24 ways
6 boys can be arranged among themselves in 6! = 720 ways
Hence, total number of seating arrangements = 120*24*720
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
-
heymayank08
- Master | Next Rank: 500 Posts
- Posts: 181
- Joined: Fri Feb 17, 2012 9:36 am
- Thanked: 1 times
- Followed by:1 members
- GMAT Score:620
Anurag@Gurome wrote:hi anurag,abcd1111 wrote: Hence, total number of seating arrangements = 120*24*720
don't u think that this will be for the arrangement in which we have to arrange among teachers, boys adn girls,
shouldn't the answer be :
5!.4!.6!.(3)
*3 because their rows need to be arranged.
please correct me if i am wrong.
-
heymayank08
- Master | Next Rank: 500 Posts
- Posts: 181
- Joined: Fri Feb 17, 2012 9:36 am
- Thanked: 1 times
- Followed by:1 members
- GMAT Score:620
Anurag@Gurome wrote:hi anurag,abcd1111 wrote: Hence, total number of seating arrangements = 120*24*720
don't u think that this will be for the arrangement in which we have to arrange among teachers, boys adn girls,
shouldn't the answer be :
5!.4!.6!.(3)
*3 because their rows need to be arranged.
please correct me if i am wrong.
-
sandeep_thaparianz
- Senior | Next Rank: 100 Posts
- Posts: 90
- Joined: Wed Mar 21, 2012 1:27 am
- Thanked: 5 times
- Followed by:2 members
heymayank08 wrote:It is already mentioned in question the pattern in which they are to be seated row wise.. So Drop *3 multiplicationAnurag@Gurome wrote:hi anurag,abcd1111 wrote: Hence, total number of seating arrangements = 120*24*720
don't u think that this will be for the arrangement in which we have to arrange among teachers, boys adn girls,
shouldn't the answer be :
5!.4!.6!.(3)
*3 because their rows need to be arranged.
please correct me if i am wrong.
-
heymayank08
- Master | Next Rank: 500 Posts
- Posts: 181
- Joined: Fri Feb 17, 2012 9:36 am
- Thanked: 1 times
- Followed by:1 members
- GMAT Score:620
sandeep_thaparianz wrote:yeah thts wat i am saying..heymayank08 wrote:It is already mentioned in question the pattern in which they are to be seated row wise.. So Drop *3 multiplicationAnurag@Gurome wrote:hi anurag,abcd1111 wrote: Hence, total number of seating arrangements = 120*24*720
don't u think that this will be for the arrangement in which we have to arrange among teachers, boys adn girls,
shouldn't the answer be :
5!.4!.6!.(3)
*3 because their rows need to be arranged.
please correct me if i am wrong.
since they are to be sated in 3 rows so the rows in thmselves can be arranged!
GMAT/MBA Expert
-
Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
Read the question carefully.heymayank08 wrote:hi anurag,
don't u think that this will be for the arrangement in which we have to arrange among teachers, boys adn girls,
shouldn't the answer be :
5!.4!.6!.(3)
*3 because their rows need to be arranged.
please correct me if i am wrong.
The question says "5 teachers are required to sit in the first row ,4 girls students are required to sit in the second row , 6 boys students are requires to sit in the last row"
This means we cannot rearrange the rows.
The teachers will always seat in the first row, the girls in the second row and the boys in the third.
Hope that helps.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
