How much money must I start out with if I want to end up with 20,000 over 5 years with and intrest rate of 5% a year.

A=P(1+r)^t

A=amount of money at end
P=amount of money to start
r=interest rate as a decimal
t=number of years
20000=P(1+.05)^5
20000=P(1.05^5)
20000/(1.05^5)=P
$15670.52=P