In a tennis tournament, each player played one game with all the other players. How many players participated in the tournament if they played 300 games in all?
According to the question, n C2 = 300, where n is the number of players (n(n - 1))/2 = 300 n2- n - 600 = 0 n2-25n + 24n - 600 = 0 n(n - 25) + 24(n - 25) = 0 (n - 25)(n + 24) n = 25
40 42 87 266 ? 5366
22, 23, 31, 57, 122, 247
32, 65 , 196, 785, ? , 23557
19.11 × 5.98 + 20.03 × 3.12 – 34.95 + 97.9 × 3.02 =?
7200 7200 3600 1200 300 ?
...0.5 1.5 5 ? 76 385
...24, 33, 50, ?, 108, 149
25, 200, 40, ?, 64, 512
1400 350 700 175 ? 87.5
...7 12 33 ? 635 3804
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