ABC Inc. has the following data for the year ended December 31, 2022:

Particulars	Amount ($)
Sales	$400,000
Cost of Goods Sold	$220,000
Gross Profit	$180,000
Operating Expenses	$75,000
Net Income	$105,000
Total Assets	$350,000
Total Liabilities	$75,000
Equity	$275,000

a) Calculate the gross profit margin and operating profit margin for the year. b) Calculate the return on assets and return on equity for the year.