The answer for this problem would be:
Orbital period if distance = 128,000,00 km and mass = Sun?
This is approximately be .85 astronomical units if converted km to au.
We will be using Kepler's third law which is:
T^2 = r^3
T^2 = .85^3
T^2 = .61
get the square root of .61
so the answer will be:
T = .78 Years which is in months is 9.36 months.