What "ROI" (Return on Investment) would you need if: 1) "I need to double my money in 10 years." % ROI 2) "I need to double my money in 8 years." % ROI
a) 7.2% and 9.0%
b) 10% and 12.5%
c) 5% and 8%
d) 15% and 20%