i am stuck on Part B and need that answer for the rest. i did Net incomeoa but i think I need NOPAT/NOA and am not sure exactly how to compute that.

$ millions Operating assets Nonoperating assets Total assets Jan. 31, 2016 $40,583 2,241 42,824 . 15,018 21,285 36,303 6,521 Feb. 01, 2015 $38,473 1,748 40,221 13,527 17,167 30,694 9,527 Operating liabilities Nonoperating liabilities Total liabilities Total stockholders' equity Sales Net operating profit before tax (NOPBT) Nonoperting expense before tax Tax expense Net income 88,999 12,024 778 4,088 7,158 Round answers to two decimal places (ex: 0.12345 = 12.35%) a. Compute return on equity. 89.21 b. Compute return on net operating assets (RNOA). 28,34 ?% c. Use ROE and RNOA to determine the nonoperating return for d. Disaggregate RNOA into components of profitability and prod