Solve.
16. Some investments pay compound interest. If interest is paid continu-
ously, then the formula t= () In (4) can be used, where t is the
number of years the money is invested, r is the annual interest rate
as a decimal. Ao is the money invested at the start of the time period,
and A is the amount of money after t years (original investment plus
interest). Carlos invested $200 in a savings account that pays an annu-
al interest rate of 4.5% (0.045). compounded continuously.
(a) How many years will it take for Carlos's investment to reach $250?
(Round your answer to the nearest tenth year.)
(b) How many years will it take for Carlos's investment to double,
that is, reach $400? (Round your answer to the nearest tenth
year.)