[問題] Form32 Sec3-Q19

[sam6521]

In the diagram above , points A, B, C, D, and E represent the five teams in a certain league in which each team must play each of the other teams exactly once. The segments connecting pairs of points indicate that two corresponding teams have already played their game. The arrows on the segments point to the teams that lost: the lack of an arrow on a segment idicates that the game ended in a tie. After all games have been played, which of the following could Not be the percent of games played that ended in a tie?

(a)10%
(b)20%
(c)30%
(d)40%
(e)50%

Ans:(a)[/img]

[Jacklin]

速解：5隊總共打了10場，己知最少有2次平手，平手次數>20%(2/10)
慢解：最多為5次平手(AC、ED、BE、BD、CE)
平手機率在20%~50%，故答案為A，參考看看！