math
posted by tom .
If I need $25,000 in 4 years. Waht amount must i invest today if the investment earns 12% compounded semiannualy?

25000=P(1+.06)^8
take log of each side
log 25000=logP+8log(1.06)
4.40=logP+.202
P= antilog(4.198)=10^4.198=15776
you can work it out more accurately with your calculator.