# Thread: Two In One

1. ## Two In One

Hi guys,

Here are my questions :-

1. If C and D are two non null sets, C - D equals ?
2. 72 matches are played. If each team plays 1 match with another team, total number of teams is ?

I have no idea about first question...so can u help me out with explanations??

Thanks in advance !

Regards,
deepz007

2. ## Re: Two In One

$2.$

$\frac{n!}{2!(n-2)!}=72$

3. ## Re: Two In One

thanx... wat abt the 1st one

4. ## Re: Two In One

I have no idea...

5. ## Re: Two In One

Originally Posted by deepz007
1. If C and D are two non null sets, C - D equals ?
The usual meaning is $C-D=C\cap \overline{D}$ where $\overline{D}$ is the complement of $D$.

Beyond that it is impossible to give any other answer.