Question

You deposit $800 in an account that pays 8% annual interest compounded quarterly. About how

long will it take for the balance to triple?

Answer 1

Answer: t = 13.73


Explination:

Youre going to use the equation A= Pe^rt
A= 2400 (800 trippled)
P= 800 because thats your deposit
E=0.08 (this is 8% as a decimal)
T= time, this is what youre going to find since its how long for it to tripple

Now lets do the math

2400. 800 e^0.08%
——— = ———————-
800 800

(Take 2400/800 this equals 3)
Now you’ll have this
3= e^0.08

Ln 3 = Ln e^0.08t
Ln3=0.08t Ln e

Now we have to get rid of 0.08

Ln 3 0.08t
——— = ————
0.08 0.08

Now in your calculator:

Ln (3) / 0.08 = 13.73265…..

So rounding this gives 13.73
T=13.73