At the first meeting of the Tennis Club, the 7 members decided to have a tournament in which every player will play a match against every other player. How many matches will there be in the tournament?

21 matches

Step-by-step explanation:

This is a combination problem where we have to select two member out of 7 members

So we want calculation of 7C2

7C2 = 7!/[ (2!) (7-2) !]

(7*6*5*4*3*2*1) / [ (2*1) * (5*4*3*2*1]

(7*6) / 2 ~ Note everything that easily cancels here!

42/2

21 matches