Two old RSM students are standing twenty feet apart when they spot Mrs. Rifkin. If they immediately run in opposite directions at speeds of 180 feet per minute and 120 feet per minute, how many minutes pass before they are 2420 feet apart?
The two students are moving away from each other at a combined speed of 180 + 120 = <<180+120=300>>300 feet per minute.
To be 2420 feet apart, it will take them 2420 / 300 = <<2420/300=8.066666666666666>>8.07 minutes. Answer: \boxed{8}.