###Human: John cuts his grass to 2 inches.  It grows .5 inches per month.  When it gets to 4 inches he cuts it back down to 2 inches.  It cost $100 to get his grass cut.  How much does he pay per year?, ### Assistant: He cuts his grass 4-2=2 inches
So he gets it cut every 2/.5=4 months
That means he gets it cut 12/4=3 times a year
So he pays 100*3=$300 per year 
 So the answer is :  300