Answer:
1,825 days
Explanation:
730 / 2 = 365 (one year, or the number of days a single revolution around the sun takes)
Now just multiply by 5
[365 · 5 = 1,825], thus 1,825 days are the duration of 5 revolutions.
The problem could also be initially expressed as:
x = (720/2) · (5) with x representing the missing value