Sam invests $4,000 in an account that earns 2.5% interest compounded continuously. to determine the amount in the account after a specified amount of time, sam uses the equation a = p e r t where a is the amount of money in the account after t years, p is the principal, and r is the rate of interest. sam has a goal of having an account balance of $12,000. which logarithmic equation can sam use to determine the number of years it will take to reach his goal? a. t = ln 3 0 . 025 b. t = 3 ln 0 . 025 c. t = 12 , 000 ( ln 4000 0 . 025 ) d. t = 3 ln 0 . 025