MathDB

1

Part of 2022 Portugal MO

Problems(1)

15 students, with different heights

Source: Portugal OPM 2022 p1

5/15/2024
Raul's class has 1515 students, all with different heights. The Mathematics teacher wants to place them in a queue so that, at the beginning of the queue, they are ordered in ascending order of heights, from then on, they are ordered in descending order and Raul, who He is the tallest in the class, he cannot be at the extremes. In how many different ways is it possible to form this queue?
combinatorics