Scoring
Cross Country races are scored based on the place of each runner competing. For example, if you win the race, you score 1 point; 2nd place gets 2 points, 3rd place gets 3 points etc. A team score is based on the top 7 runners from each team. Of those, the top 5 are scored, while the remaining 2, 6th and 7th place, are able to displace runners on other teams.
Let's take a look at the below scenario to see how we'd score it.
Hopkinton Wins
In the above co-ed race, we have a dual meet between Hopkinton and Norwood. Hopkinton is led by Steve who scores 1 point, followed by Joan with 3, Roger with 5, Grete with 6 and Kenenisa with 11 for a total of 26 points. Norwood is led by Eliud with 2 points, followed by Sydney with 4, Meb with 7, Allyson with 8 and Jakob with 9 for a total of 30 points. You can see that although you might not win a race, XC is a team sport and the it takes a team effort to do well!
Displacement
Notice that Norwood had 6 runners before Hopkinton's 5th (Kenenisa) and Zola displaced Kenenisa 1 spot to 11th place overall. If we had only been counting the top 5, we would have taken Zola out of the standings altogether, as she was Norwood's 6th runner but because of the displacement rule, the 6th and 7th runner on a team displace runners from other teams.
Ties and the Perfect Score
Another thing to remember when scoring a dual meet is that in the event of a tie, the times of the 6th runner on each team are compared, and the team that has the fastest time, wins. In XC a perfect score is when your top 5 take the top 5 places in the race: 1,2,3,4,5 for a total of 15 points, meaning the second place team would get a maximum of 50 points: 8,9,10,11,12 if your runners also placed 6th and 7th. Hard to do, but not impossible!
Invitationals
In an invitational, where there are more than two teams, it get's a bit trickier, but the idea is the same. You score all runners who are running as part of a team and the low score wins. Although 15 points is still a perfect score, because there are more teams and therefore more displaced runners, the second team can get far higher that 50 points. It is not uncommon for teams to score in the hundreds of points at a large invitational meet.