You deposit 1000 in a fund earning 575 How long will it take

You deposit $1,000 in a fund earning 5.75%. How long will it take to double your money?

Solution

Let us suppose that it will take n years to get double. Hence,

1000(1+0.0575)^n=2000

or,log1000+nlog(1.0575)=log2000

or, 3+0.024280n=3.30102

or, n=0.301029/0.024280=12.3

Hence it will take almost 12.3years to get double