Question

How many years will it take an investment of $1,000 to double itself when interest is compounded annually at 8%?
18.5 yrs
9 yrs
7.2 yrs
1.85 yrs

Answer 1

\[2=(1.080^y\]
\[y=\frac{ln(2)}{ln(1.08)}\]

Answer 2

second step is change of base formula. to solve \[b^x=A \] for x the solution is
\[x=\frac{ln(A)}{ln(b)}\]

Answer 3

to get the decimal number you need a calculator.

Answer 4

about 9