# An original sample of K-40 has a mass of 25.00 grams. After #3.9 xx 10^9# years, 3.125 grams of the original sample remains unchanged. What is the half-life of K-40?

##### 1 Answer

Jun 21, 2017

#### Explanation:

From

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Use the rate constant (k) in the half-life equation ...

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