Wendi lives on a plot of land that is 200 feet by 900 feet of grassland.  She raises rabbits on her property by allowing the rabbits to graze on the grass that grows on her land.  If one rabbit can eat enough grass to clear ten square yards of lawn area per day, and Wendi owns 100 rabbits, how many days would it take for Wendi's rabbits to clear all the grass off of her grassland property?
One square yard is the same as 3 feet by 3 feet, or 3*3=<<1*3*3=9>>9 square feet.
Ten square yards is 9*10=<<10*9=90>>90 square feet.
Therefore, 100 rabbits can clear 100*90=<<100*90=9000>>9,000 square feet of grassland per day.
A 200 ft by 900 ft area is 200*900=<<200*900=180000>>180,000 square feet.
Thus, 180,000 sq ft can be cleared by 100 rabbits in 180,000/9000=<<180000/9000=20>>20 days
#### 20