Gravitational force between two objects

Question

How will gravitational force between two objects change when one of the objects adds 3 times more mass and moves further 3 times the original distance

Answer 1

the gravitational force assuming the same objects mass m1 = m2 = m and same distance is F1 = k (m1m2)/ r² or

F1 = k (m²)/ r² . If one of the objects is three times in mass than the other then m2 = 3m1 = 3m and if it moves 3 times the distance then r = 3r

substituting you get F2 = k( m1)(3m1)/ (3r)² = k(m)(3m)/( 9r²) = k ( 3m²)/ 9r² simplifying you get

F2 = k (m²) / 3 r² , comparing this with original equation F1 = k (m²)/ r² and F2 = k (m²) / 3 r² divide F1 by F2 you get F1 / F2 = k (m²)/ r² / k (m²) / 3 r² simplifying , F1 / F2 = 3 and F2 = 1/3 F1 , therefore the force is reduced to 1/3 of the original force