An oil burner in a housing development burns 76 gallons of fuel oil per hour. At 9am on a very cold day, the superintendent asks the housing manager to put in an emergency order for more fuel oil. At that time, he report that he has on hand 266 gallons. At noon, he again comes to the manager, notifying him that no oil has been delivered. The Maximum amount of time that he can continue to furnish heat without receiving more oil is