A high school sponsored a badminton tournament. After each round, one-half of the players were eliminated. If there were 64 players at the start of the tournament, which equation models the number of players left after round 3?
(1) y=64(1-.5)^3
(2) y=64(1+.5)^3
(3) y=64(1-.3)^.5
(4) y=64(1+.3)^.5