$1)$ For fiscal year $2015,$ Walmart Stores Inc. $($WMT$)$ had total revenues of $$484\mathrm{.}65$ billion, net income of $$16\mathrm{.}36$ billion, total assets of $$203\mathrm{.}49$ billion, and total shareholder$$s equity of $$81\mathrm{.}39$ billion.

Please calculate Wal$-$Mart$$s ROE directly, and using the DuPont Identity. Please show all your process.

$2)$ For fiscal year $2015,$ Costco Wholesale Corporation had a net profit margin of $2\mathrm{.}05\%,$ asset turnover of $3\mathrm{.}48,$ and a book equity multiplier of $3\mathrm{.}15.$

Use this data to compute Costco's ROE using the DuPont Identity. Please show all your process.

$3)$ Compare the information you obtained in $1)$ and $2),$ use the DuPont Identity to understand the difference between the two firms$$s ROEs