# Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Show all calculations leading to a solution.

##### 1 Answer

Aug 22, 2017

#### Answer:

90 days

#### Explanation:

All radio decay follows 1st order kinetics and therefore is supported by the integrated rate law of a 1st order decay trend. The classic form of the 1st order decay equation is

Given

From the 1st order decay equation ...

=>