If one team has its five runners finish in the top five places, the resulting score for that team will be 15 (1+2+3+4+5=15), which is a perfect score.
In a dual meet, should one team have its seven runners finish in the top seven places—before any of the opponent’s five scorers finish—the resulting score of the meet will be 15-50. The opposition would score 8+9+10+11+12=50. This is a shutout in cross-country. In a dual meet no team can score fewer than 15 points, or more than 50 points.
In a dual meet, if one team takes the top three places, they automatically win, no matter how far back their 4th and 5th runners finish. This is because their score cannot be worse than 1+2+3+11+12 (29), while the other team’s score can be no better than 4+5+6+7+8 (30).
Although the 6th and 7th runners from a team cannot change their own team’s score, they have an important role. By placing before a scoring runner from another team, they cause the opposing team’s score to be higher.
For example:
Even though Team B’s sixth runner (10th place) did not directly contribute to Team B’s score as far as points, he contributed to the overall victory. By placing 10th, he caused Team A's fifth place runner to come in 11th, thereby causing Team A to score more points (11 instead of 10). Team B's sixth runner "displaced” Team A’s fifth runner, who, instead of finishing 10th, finished 11th.
The below example shows displacement and a tie-breaker.