A certain game is played between pairs — one pair plays on a team against another pair. If there are $6$ players available, and every pair has to play with every other pair, what is the total number of games which must be played ?
MY APPROACH:
$6$ players can be divided into $3$ pairs in $\frac{6!}{2!2!2!}$ ways.Moreover 3 pairs may play in $3$ ways with each other.The answer evaluates to $\frac{6!}{2!2!2!}.3=270$.
However this answer is wrong.Can you point out the mistake?
Best Answer
You are very close to being correct. The error is
This is wrong because you are counting each way of dividing them into 3 pairs in $6$ different ways. So you should divide by $6$ to get the correct number of ways to group them into 3 pairs.
Other than this, your calculation is correct.