Math
posted by Will .
How much must you deposit in an account
that pays 6% semiannual interest, compounded annually, to have a balance of $9000 in 15 years?

P = Po(1+r)^n.
P = $9,000.
r = (2*6%/100%) = 0.12 = Annual % rate expressed as a decimal.
n = 1Comp./yr * 15yrs = 15 Compounding
periods.
P = Po(1.12)^15 = 9,000.
Po = 9000 / (1.12)^15 = $1644.27.