Question

The separation between the masses is tripled. How is the magnitude of gravitational force between them affected? How?

Answer 1

Assuming that these two bodies are in space, not on Earth. Gravitational force is inverse proportional with distance squared. The formula is

F(d=r) = Gmm/r^2

So, if the disctance goes from 1r to 3r then force will be

F(d=3r ) =Gmm/(3r)^2

=Gmm/9r^2

It will be one ninth of previous force