If the 40 kg boy were in a spacecraft 5.0r from the center of the earth, what would his weight be?

Weight is a measure of acceleration, so the answer depends on the acceleration of the spacecraft. If the spacecraft were in orbit, the boy would weigh zero, i.e. would be weightless. The same is true if the spacecraft were falling directly toward the Earth. 

If the spacecraft were holding itself stationary relative to the Earth-Sun line (by firing its engines, for instance), the boy would weigh 1/5 * 1/5 as much as on the Earth's surface, since he would be five times as far away. so he would weigh .2 * .2 * 40 * 9.8 = 15.7 newtons. (The 9.8 is the conversion factor for kilograms to newtons here on Earth's surface.)