RivalryofTroll
Sleep Deprived Entity
- Joined
- Feb 10, 2011
- Messages
- 3,804
- Gender
- Male
- HSC
- 2013
- Uni Grad
- 2019
140What do the answers say?
Students helping students, join us in improving Bored of Studies by donating and supporting future students!
140What do the answers say?
Is there no working for the answers?
Sorry - I'm confused as to why it's this.Suppose A and B are in a circle, and DON'T want to sit next to each other.
Then we do Total - together = 9! - 8!2!
none. no working out.Is there no working for the answers?
Yea it should defs be 8C5.none. no working out.
8C5 should be right though... dam dodgy answers...
XXXXX(AB)XXXSorry - I'm confused as to why it's this.
Oh - thanks a lotXXXXX(AB)XXX
So we have 9 elements there (we count the AB as a group since they are together), but they are in a circle, so 8!.
Now A and B can swap, so 2!.
Therefore 8!2!.
well, isn't there really just one difference to 'line' questions? (i.e. one is excluded)Oh - thanks a lot![]()
Don't know why, but I always get confused with circles.
Thanks heaps![]()
If you're working on a single case and doing everything at once, then multiply.Question: How do we know when to use the multiplication principle? Is there a certain way that the question is asked to hint us to use it?
10 people to choose to form 6.A committee of 6 is to be selected from 10 people of whom A and B are two. How many committees can be formed excluding A if B is included?
Doesn't the question ask to include B?10 people to choose from 6.
For this question, there are two cases:
When B is included (A must be excluded) - 8 (b/c B has to be included and A excluded) to choose from 5 ( B is already in) .'. 8C5
When B is excluded (A doesn't have to be excluded)- 9 (B is excluded) to choose from 6 (anyone else can be chosen) .'. 9C6
= 8C5+9C6 = 140
Nope, it just says IF B is included , then A is excludedDoesn't the question ask to include B?
Thanks very much.10 people to choose to form 6.
For this question, there are two cases:
When B is included (A must be excluded) - 8 (b/c B has to be included and A excluded) to choose from 5 ( B is already in) .'. 8C5
When B is excluded (A doesn't have to be excluded)- 9 (B is excluded) to choose from 6 (anyone else can be chosen) .'. 9C6
= 8C5+9C6 = 140
Nope, it just says IF B is included , then A is excluded
but B can be excluded too.
?A committee of 6 is to be selected from 10 people of whom A and B are two. How many committees can be formed excluding A if B is included?
Refer to my post about placement of commas.
English... haunts you to this day.I think it depends on how you read the question, and placement of commas.
How I interpreted it:
A committee of 6 is to be selected from 10 people of whom A and B are two. How many committees can be formed excluding A, if B is included?
What the question presumably tried to communicate
A committee of 6 is to be selected from 10 people of whom A and B are two. How many committees can be formed, excluding A if B is included?