The degree is positive and even
The degree is negative and odd
Follow these steps: Have faith in me
In the product development department, there will be 12 engineers left.
For team one, they have to compete against 12 different teams, which amounts to 12 days of play.
Team two, which has already played team one, will only need to participate in 11 more days.
Team three has already faced teams one and two, leaving them with 10 additional days.
Continuing this pattern results in a total of 12 + 11 + 10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 78 days.
Alternatively, you can calculate the number of unique matches as 13*12 / 2! = 78.
Another way is by calculating combinations of 13 taken 2 at a time: 13C2 = 13! / [(2!)(11!)] = 13*12*11! /(2!*11!)= 13*12/2 = 78.
