Question

How long it will take for $300 to double when invested at 6% annual interest compounded twice a year?

Answer 1

change the interest the half yearly r = 3%

then 600 = 300(1 + 3/100)^n

2 = 1.03^n

to find n you need logarithms

ln(2) = nln(1.03)

n = ln(2)/ln(1.03)

n = 23.44 6 month periods.

or its 11.72 years

the alternative is to set up the equation in a calculator and keep change n until you get the desired value of 2

Answer 2

@campbell_st Thank you very much