page10gravitation module q3 how is there field inside shell+q2

In part 1.
Force ecperienced by mass m’ will be multiplied with net gravitational intensity (Gravitational intensity due to hollow sphere would be zero inside but intensity due to solid sphere would be measure from the surface of it).
in part 2.. calculate the gravitational intensity due to the effect of inner solid sphere.
in part 3.. calculate the gravitational intensity due to both the sphere and simply multiply by mass m’..