Your math is wrong by almost an order of magnitude.
The rule of 72 is handy for thinking about growth rates. Divide 72 by the rate to get the doubling time.
At 10%, it will double approximately every 72/10 = 7.2 years. So about 7 doublings in 50 years = 2^7 = 128. So you can estimate in your head that the answer is roughly $128,000 and $17,000 is completely wrong.
Ah, yes I meant to say 30 years, not 50. Thanks for the correction. the rule of 72 is a good one, and is what I actually used, the problem is that I did the math on 30 years but 50 years was a better number to use to make my comment, but I didn't update the number :(
Your math is wrong by almost an order of magnitude.
The rule of 72 is handy for thinking about growth rates. Divide 72 by the rate to get the doubling time.
At 10%, it will double approximately every 72/10 = 7.2 years. So about 7 doublings in 50 years = 2^7 = 128. So you can estimate in your head that the answer is roughly $128,000 and $17,000 is completely wrong.