Question

what anual rate of interest is required to triple an investment in 12 yrs
a) 4.794% b)9.578% c)5.946% d)9.155%

Answer 1

compounded how?

Answer 2

i think A=P(1+r/n)^ nt

Answer 3

are u sure b) is 9.578 and not 9.587?

Answer 4

compounded anually, semianually, monthly, daily, contiously?

Answer 5

contiously?

Answer 6

linhphan is b) 9.587 or 9.578

Answer 7

Okay, let's solve it that way=
\[A=Pe^{rt}\]
since we want triple
\[3P=Pe^{rt}\]
\[3=e^{rt}\]
now plug in number
\[3=e^{r12}\]

Answer 8

ln 3=12r ln e
ln 3= 12 r
ln 3 /12 =r

Answer 9

this is what I meant
\[\frac{ln 3}{12}\]

Answer 10

that gives 9.155%

Answer 11

So, in this kind of problem, works is much more important than mere answer