MathDB

1

Part of 2005 Portugal MO

Problems(1)

2005 people at a SuperRockPop concert

Source: Portugal OPM 2005 p1

5/19/2024
In line for a SuperRockPop concert were 2005 people. With the aim of offering 33 tickets for the "backstage", the first person in line was asked to shout "Super", ` the second "Rock", ` the third "Pop", ` the fourth "Super", ` the fifth "Rock", ` the sixth "Pop" and so on. Anyone who said "Rock" or "Pop" was eliminated. This process was repeated, always starting from the first person in the new line, until only 33 people remained. What positions were these people in at the beginning?
combinatorics