Identify next three numbers in this sequence: 2, 6, 3, 9, 6, 18, 15… 45, 22.5, 67.5
19, 16, 20
40, 37, 111
45, 42, 126

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?