Answer:
Step-by-step explanation:
20 matches, so there is 40 players in the club.
First number too chole 2 first players for match you can do it in .
Now you have 38 players, becaus you chose 2. Now frim 38 player you can choose new 2 in ways. So and on... you will have ways to choose 20 matches in:
.
4
4+3a=16
-4. -4
3a=12
/3. /3
a=4
the answer is 210 m (3)