Which situation can be modeled by a linear function? (1) The population of bacteria triples every day. (2) The value of a cell phone depreciates at a rate of 3.5% each year. (3) An amusement park allows 50 people to enter every 30 minutes. (4) A baseball tournament eliminates half of the teams after each round.

(3) An amusement park allows 50 people to enter every 30 minutes.