Timmy has $50, he puts it in a bank and profits 2,5% every year. How many years does it take until Timmy has $100?
Final Amount = Initial Amount · ( 1 + rate )number of compounding periods
100 = 50 · ( 1 + 0.025 )n
100 = 50(1.025)n
2 = (1.025)n
log(2) = log( 1.025n )
log(2) = n · log(1.025)
n = log(2) / log(1.025)