Answer:
a.F/9
Explanation:
Hello, I can help you wit this
the gravitational Force is described by the next equation

Where, G is the universal gravitational constant, M1 and M2 are the masses of the objects, and r is the distance between then.
Step 1
time 1
Let
m1= mass of the asteroid 1
m2= mass of the asteroid 2
distance 1=r1
put the values into the equation to find the force

Step 2
time 2
r2=3r1

Step 3
compare the forces

a.F/9
here it is observed that the force is inversely proportional to the square of the distance, at double distance, it is divided into 4, triple in 9, etc.
Have a great day.