Find the number of ways in which 6 boys and 6 girls can be seated in a row so that all the girls are never together.
Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
Find the number of ways in which 6 boys and 6 girls can be seated in a row so that all the girls are never together.
Attempt:
total number of ways - number of ways in which all girls are together
$= 12! - 2!times(6!)times (6!)$
But answer given is $12! - 7!6!$
Is the given answer wrong?
combinatorics
add a comment |Â
up vote
2
down vote
favorite
Find the number of ways in which 6 boys and 6 girls can be seated in a row so that all the girls are never together.
Attempt:
total number of ways - number of ways in which all girls are together
$= 12! - 2!times(6!)times (6!)$
But answer given is $12! - 7!6!$
Is the given answer wrong?
combinatorics
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Find the number of ways in which 6 boys and 6 girls can be seated in a row so that all the girls are never together.
Attempt:
total number of ways - number of ways in which all girls are together
$= 12! - 2!times(6!)times (6!)$
But answer given is $12! - 7!6!$
Is the given answer wrong?
combinatorics
Find the number of ways in which 6 boys and 6 girls can be seated in a row so that all the girls are never together.
Attempt:
total number of ways - number of ways in which all girls are together
$= 12! - 2!times(6!)times (6!)$
But answer given is $12! - 7!6!$
Is the given answer wrong?
combinatorics
combinatorics
asked 1 hour ago
Abcd
2,75011129
2,75011129
add a comment |Â
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
3
down vote
accepted
With any constraint the number of possible combination is $12!$
If all the girls are together, we can think the set to be of $6+1$ members which can be arranged in $7!$ ways
and again the $6$ girls can be arranged in $6!$ ways
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
add a comment |Â
up vote
2
down vote
All the girls together means a sequence of 6 girls in a row.
This sequence can start at position 1, 2, 3, 4, 5, 6 and 7.
There are $6!$ ways to place the girls and $6!$ ways to place the boys.
So you have $7 cdot 6! cdot 6! = 7! cdot 6!$ possible ways to violate the rule.
Thus there are $12! - 7! cdot 6!$ ways that respect the rule.
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
With any constraint the number of possible combination is $12!$
If all the girls are together, we can think the set to be of $6+1$ members which can be arranged in $7!$ ways
and again the $6$ girls can be arranged in $6!$ ways
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
add a comment |Â
up vote
3
down vote
accepted
With any constraint the number of possible combination is $12!$
If all the girls are together, we can think the set to be of $6+1$ members which can be arranged in $7!$ ways
and again the $6$ girls can be arranged in $6!$ ways
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
add a comment |Â
up vote
3
down vote
accepted
up vote
3
down vote
accepted
With any constraint the number of possible combination is $12!$
If all the girls are together, we can think the set to be of $6+1$ members which can be arranged in $7!$ ways
and again the $6$ girls can be arranged in $6!$ ways
With any constraint the number of possible combination is $12!$
If all the girls are together, we can think the set to be of $6+1$ members which can be arranged in $7!$ ways
and again the $6$ girls can be arranged in $6!$ ways
answered 1 hour ago
lab bhattacharjee
218k14153268
218k14153268
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
add a comment |Â
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
Reminds me of math.stackexchange.com/questions/697433/…
– lab bhattacharjee
50 mins ago
add a comment |Â
up vote
2
down vote
All the girls together means a sequence of 6 girls in a row.
This sequence can start at position 1, 2, 3, 4, 5, 6 and 7.
There are $6!$ ways to place the girls and $6!$ ways to place the boys.
So you have $7 cdot 6! cdot 6! = 7! cdot 6!$ possible ways to violate the rule.
Thus there are $12! - 7! cdot 6!$ ways that respect the rule.
add a comment |Â
up vote
2
down vote
All the girls together means a sequence of 6 girls in a row.
This sequence can start at position 1, 2, 3, 4, 5, 6 and 7.
There are $6!$ ways to place the girls and $6!$ ways to place the boys.
So you have $7 cdot 6! cdot 6! = 7! cdot 6!$ possible ways to violate the rule.
Thus there are $12! - 7! cdot 6!$ ways that respect the rule.
add a comment |Â
up vote
2
down vote
up vote
2
down vote
All the girls together means a sequence of 6 girls in a row.
This sequence can start at position 1, 2, 3, 4, 5, 6 and 7.
There are $6!$ ways to place the girls and $6!$ ways to place the boys.
So you have $7 cdot 6! cdot 6! = 7! cdot 6!$ possible ways to violate the rule.
Thus there are $12! - 7! cdot 6!$ ways that respect the rule.
All the girls together means a sequence of 6 girls in a row.
This sequence can start at position 1, 2, 3, 4, 5, 6 and 7.
There are $6!$ ways to place the girls and $6!$ ways to place the boys.
So you have $7 cdot 6! cdot 6! = 7! cdot 6!$ possible ways to violate the rule.
Thus there are $12! - 7! cdot 6!$ ways that respect the rule.
answered 1 hour ago
Ronald
643510
643510
add a comment |Â
add a comment |Â
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2970498%2ffind-the-number-of-ways-in-which-6-boys-and-6-girls-can-be-seated-in-a-row-so-th%23new-answer', 'question_page');
);
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password