Helicopteros Sanitarios, an ambulance service in Fuengirola, Spain, receives an average of 20 calls per day during the time period 6 p.m. to 6 a.m. for assistance. For any given day what is the probability that fewer than 15 calls will be received during the 12-hour period? What is the probability that more than 25 calls during the 12-hour period will be received?