$2.$Chapter $8$ Investing Activities Walmart makes significant investments in operating capacity, primarily via investments in property, plant, and equipment $($PP&E$),$ but also via investments in wholly and partially owned subsidiaries. The online appendix in Walmarts January $31,2021,$ Consolidated Financial Statements and accompanying notes, describes these significant investments. Perform the following:a$.$Estimate the average total estimated useful life of depreciable PP&E ending January $31,2021.$ Does the estimate reconcile with stated accounting policy on useful lives for PP&E$?$ Explain.b$.$Estimate the proportion of PP&E that has been used up and estimate its remaining useful life. How might an analyst use this information?c$.$Has Walmart recognized impairment of PP&E or goodwill during the fiscal year ending January $31,2021?$ Why is it important for the analyst to know the answer to this question?