When the interest on an investment is compounded continuously, the investment grows at a rate that is proportional to the amount in the account, so that if the amount present isP, then

dP/dt=kP

wherePis in dollars,tis in years, andkis a constant. If $150,000is invested (whent= 0)and the amount in the account after18yearsis $368,940, find the function that gives the value of the investment as a function oft. (Round your value ofkto two decimal places.)

P=

What is the interest rate on this investment?