16. The present value interest factor is computed as: 17. One year ago, you invested S1,800. Today it is worth $1,924.62. What rate of interest did you earn? A. 6.59% B. 6.67% C. 6.88% D. 6.92% E. 7.01% 18. Forty years ago, your mother invested $5,000. Today, that investment is worth $430,065.11. What is the average annual return she earned on this investment? A. 11.68% B. 11.71% C. 11.78% D. 11.91% E. 12.02%