Future Value, Interest Rate

Question

How many years would it take $1,000 to grow to $5,000 assuming an annual interest rate of 15%?

Answer 1

1000*(1.15)^t = 5000

 

(1.15)^t = 5

 

log (1.15)^t = log 5

 

t * log (1.15) = log 5

 

t = log 5 / log (1.15) = 11.515