Business Statistics question below?

An airline, in response to penger concern, conducts realistic tests to determine the time needed to evacuate a Boeing 737. Average evacuation time in the past has been 100 seconds with a standard deviation of 15 seconds. The FFA requires tests that show a planeload of pengers can be evacuated in 95 seconds. If the airline conducts a sample of 30 tests, what is the probability that the average evacuation time will be 95 seconds or less?