A large iron sphere was placed a certain from a huge boulder. The force of gravity felt by the sphere from the boulder is 0.2N. The mass of the boulder is doubled and the distance is doubled. Which statement is correct?

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.

From my calculation, i got 3.655moles

Answer phase of matter