Ratio	2019	2020
Operating profit margin	4.54%	5.06%
ROA	7.96%	5.74%
Current ratio	1.12:1	1.23:1
Quick ratio	0.28:1	0.23:1
Average Inventory turnover period	36.51 days	35.26 days
Average Accounts Receivable settlement period	0.69 days	0.73 days
Average Accounts Payable settlement period	40.62 days	43.04 days

The following ratios are computed based on the financial data of SuperMart, a large company that operates in food and staple retailing.

a. The operating profit margin and ROA showed opposite trends in 2019-2020. Provide two possible explanations to account for the disparity.

b. The company did not have a liquidity issue despite a low quick ratio in both years, why do you think this might be the case.