# Greg bought a gold coin for $9,000. If the value of the coin increases at a constant rate of 12% every 5 years, how many years will it take for the coin to be worth $20,000?

##### 1 Answer

Aug 24, 2017

Approximately 35 years (35.23).

#### Explanation:

If the price increases by 12% every five years, to get the value after five years we multiply by

So the value after

So we now want to find out when the value will be $20000. So

Take logs of both sides and use rules of logs on LHS to bring down the n:

The coin reaches $20000 value after roughly 35 years.