A company's inventory is audited, and the following information is obtained:

Beginning inventory: $100,000
Purchases made during the year: $500,000
Ending inventory: $80,000
Sales made during the year: $700,000
Gross profit margin: 30%
Calculate the following:

a) Cost of goods sold for the year
b) Gross profit for the year
c) Inventory turnover ratio

Show all calculations and express the answer to the nearest dollar or ratio as applicable.