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? Let's answer step by step:
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. The answer: 300.