If the masses of the objects in Problem 35 are both increased by a factor of by what fac...

If the masses of the objects in Problem 35 are both increased by a factor of by what factor does the gravitational force change? Do not use a calculator to solve this problem!

(reference problem 35)

Two small objects of mass 20 kg and 30 kg are a distance 1.5 m apart. What is the gravitational force of one of these objects on the other?