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The 72 Rule) With the help of the approximation In(1r) - 32 we will use in class and the value In(2) 0.69, show that the number of periods (e.g. years) n required for an investment at interest rate r-10% (per period) to double in value is n 72/(100 * r). Create an Excel spreadsheet to assess the sensitivity of this approximate formula to the value of the interest rate r. For what value of the interest rate r is the "72 Rule" formula closest to the 'true' n? The 72 Rule) With the help of the approximation In(1r) - 32 we will use in class and the value In(2) 0.69, show that the number of periods (e.g. years) n required for an investment at interest rate r-10% (per period) to double in value is n 72/(100 * r). Create an Excel spreadsheet to assess the sensitivity of this approximate formula to the value of the interest rate r. For what value of the interest rate r is the "72 Rule" formula closest to the 'true' n