Answer
10%
Work Step by Step
The unknown interest rate is calculated by initially dividing the future value of 1,000,000 by the present investment of 239,392 which is 4.17725: the amount $1.00 would accumulate to in 15 years at an unknown interest rate. The factor or its approximate is then located in the Future Value of 1 Table by reading across the 15-period line to the 10% column; thus, 10% is the interest rate Elvira must earn on her investment to gain millionaire status.
