The activity time of a summer camp is 15 days, and the sales staff dormitory is equipped with air conditioning. If a dormitory is opened for 2 hours longer than originally planned, the total time to turn on the air conditioner will exceed 150 hours. If the opening time of the air conditioner is 2 hours less than the original planned total time, the total opening time of the air conditioner is less than 120 hours. How many hours did the air conditioner turn on every day?