Answer:
This question can be solved by Kepler's Third law of planetary motion which cites that The square of time period of a planet is directly proportional to cube of it's mean distance
Let the Mean distance of Earth be x.
Time period of earth = 1 earth year
Given, Mean distance of Saturn = 9x
Let the Saturn years = y yearth years.
Now,
1² / y² = x³ / (9x)³
1/y²= x³/729x³
1/y²=1/729
y² = 729
y² = 27²
y = 27 .
Therefore, The Saturn years would be 27 times longer than earth. or Saturn year = 27 Earth years = 27*365 = 9855 Earth days
