$ millions	May 31, 2015	May 31, 2014
Operating Assets	56,535	51,447
Non-operating Assets	54,368	38,819
Total Assets	110,903	90,266
Operating liabilities	19,847	18,722
Non-operating liabilities	41,958	24,097
Total liabilities	61,805	42,819
Total stockholder equity	48,663	46,878
total revenue	38,226
Operating income before tax	13,871
Nonoperating income before tax	1,037
Tax expertise	2,896
Net income	9,938

a. Compute return on equity

b. Apply DuPont disaggregation into return on assets and financial leverage

c. calculate the profitability and productivity components of return on equity

d. confirm the return on equity from part a with full DuPoint disaggregation: ROE = PM X AT X FL