Answer:
It decreases by a factor of 4
Step-by-step explanation:
The gravitational force between two masses is given by

where
G is the gravitational constant
m1, m2 are the two masses
r is the separation between the two masses
In this problem, the distance between the masses is doubled, so
r' = 2r
Substituting into the equation, we see that the new force is

So, the force decreases by a factor of 4.