how to determine the ratio between two different masses

Question

A planet has masses ( m1) and has at a distance ( r1), from the sun. a second planet has mass(m2) equal to (m1) at a distance of r2=2r from the sun . Determine the ratio of the gravitational force experience by the planet .

Answer 1

M = mass of sun

 

F₁ = GMm₁/r₁²

 

F₂ = GMm₂/r₂² 

 

Evaluate F₁/F₂ or F₂/F₁ by substituting the stated values of m₁ , m₂, r₁, and r₂.  You should be able to finish from here.