there are 20 players in a chess group , and each player plays each of the others once . given that each game is played by two players , how many total games will be played ?
"20 players are there . two players play one game with one another . so 20 c 2 = 20 * 19 / 2 = 190 so option c is correct"
divide(multiply(20, subtract(20, const_1)), const_2)