Question 1137325: The amount of money invested in a certain account increases according to the following function, where
y0
is the initial amount of the investment, and
y
is the amount present at time
t
(in years).
=yy0e0.045t
After how many years will the initial investment be doubled? Do not round any intermediate computations, and round your answer to the nearest tenth.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! this is the continuous compounding formula
y=yo*e^(0.045t), y/yo=e^(0.45t)
when it doubles, y/yo=2
so 2=e^(0.045t)
ln both sides
ln2=0.045t
t=15.4 years (rule of 70, where interest rate (in %)* time(years)=70 as a quick way to get a sense of doubling time.
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