Answer:
4/3
Step-by-step explanation:
We already know aforehand that the acceleration due to gravity on the surface of a planet is given as
GM/r²,
Now, if the mass is quadrupled, we would have
G4M/r²,
If the radius is then tripled, we would have again
G4M/3r²
And that is what we have, now, to get the factor that the acceleration changes is simply to compare it with the primary equation
HM/r² = G4M/3r²
And thus, we find out that the factor is 4/3 or 1.333