7 chess players take part in a tournament. Every player plays twice with each of his opponents. How many games are to be played? Select the correct option:  A) 40  B) 48  C) 45  D) 42  E) 22
Though 2*(7C2) is the correct approcah to do this, but for people like me who find Perm, Comb n Prob a nightmare, an easy approach can be used.   The first guy has to play 2 matches with the rest of 6, so he'll play 12matches.   Similarly, second guy has to play with the rest of 5 as his 2 games with the first guy are already played. So he plays 10 matches.   This continues like this and the total matches are 12+10+8...+2   12+10+...+2 = 2(6+5+...+1) = 2((6*7)/2) = 6*7= 
<gadget id="calculator">6*7</gadget>
<output>42</output>
42.   ANSWER:42
<result>D</result>
7 chess players take part in a tournament. Every player plays twice with each of his opponents. How many games are to be played?