During a typical 2.5-h airplane flight, passengers are exposed to 65 J>h of radiation above the background

During a typical 2.5-h airplane flight, passengers are exposed to 65 µJ>h of radiation above the background radiation they receive on the ground, mostly from cosmic ray protons that are otherwise absorbed by the atmosphere before they reach the surface.
(a) What dose in rad is received by a 75-kg person during the flight?
(b) What is the person's equivalent dose in rem? Compare your answer to the 2.0-mrem dose typical of a chest X-ray.