Question

A uniform sphere of mass M and radius R is surrounded by a concentric spherical shell oof same mass but radius 2R . A point mass m is kept at a distance x(R)
in the region bounded by spheres. The net gravitational force on the particle is.?

Answer 1

Since the point mass is kept at a distance x>R (suppose, as it is not clear in question) in the region bounded by spheres.
i.e.mass is inside the cavity of concentric sphere, so the force here due to this sphere is zero.
 Thus, the force on the mass will be only due to the inner sphere.
F=(GMm)/x²

Answer 2

The force of attraction due to hollow spherical shell of uniform density,on a point mass situated inside it is zero

Explanation for virtuoso's answer