On a certain planet if each year has 9 months and each month has 15 days how many full years have passed after 700 days on this planet

First we must find how much days are in a year. To do this, we must multiply the months by the days:
9*15 = 135
Next we divide the 700 days by the 135 days per year to find the total amount of years that has passed.
700/135 = 5.185...
Now we know that 5.185 years have passed, but the amount of full years has been 5 full years have passed after 700 days in this planet.