While Steve and LeRoy are fishing 2 miles from shore, their boat springs a leak, and water comes in at a constant rate of 15 gallons per minute. The boat will sink if it takes in more than 40 gallons of water. Steve starts rowing toward the shore at a constant rate of 6 miles per hour while LeRoy bails water out of the boat. What is the slowest rate, in gallons per minute, at which LeRoy can bail if they are to reach the shore without sinking?