Dawn should buy gold at a high altitude and sell at a low altitude.
Explanation:
Newton’s Law of Universal Gravitation states that the force of gravity acting between the earth and any other object is directly proportional to the mass of the earth. The force of gravity acting between the earth and the object is directly proportional to the weight of the object, and inversely proportional to the square of the distance separating the centers of the earth and object.
Dawn learnt that distance influences the weight of the object from the center of the Earth. She decided to buy gold at one altitude and sell it at another altitude. So to benefit from her purchasing, Dawn should buy gold at high altitude and sell at low altitude.