Question

1. How long does money in a savings account take to double itself at 4% interest compounded annually? [use the formula A=P(1+i)^n]. Round answer to nearest tenth.

Answer 1

You need to find n so that
\[
P(1+i)^ n = 2 P\\
1.04^n= 2\\
\]
We cancelled by P.
Can you finish it?

Answer 2

Im lost. i got 50.99346 and my answer choices are 1.9 3.1 5.7 17.7 23.2

Answer 3

Sorry, this is the correct solution for n
\[
n \ln (1.04) =\ln(2)\\
n = \frac {\ln(2)}{\ln (1.04)}
\]

Answer 4

\[n =\frac {0.693147}{0.0392207}=17.673
\]
The answer 17.7