Your parents will retire in 16 years. They currently have $330,000 saved, and they think they will need $1,700,000 at retirement. What annual interest rate must they earn to reach their goal, assuming they don't save any additional funds?

so I set it up at 1,700,000=330,000 x (1 + r)^16

however, I can't seem to get the answer right. Can anyone help with this?