Answer:

Explanation:
First of all, let's remind that:
- The kinetic energy of an object is given by
, where m is the mass and v is the speed
- The momentum of an object is given by 
- The inertia of an object is proportional to its mass, so we can write
, where k just indicates a constant of proportionality
In this problem, we have:
-
(the two objects have same kinetic energy)
-
(A has three times the momentum of B)
Re-writing both equation we have:

If we divide first equation by second one we get

And if we substitute it into the first equation we get

So, B has 9 times more mass than A, and so B has 9 times more inertia than A, and their ratio is:
