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March 27, 2015

March 27, 2015

Posted by **Becky** on Thursday, October 10, 2013 at 11:36am.

How old is the rock in years?

- Chemistry -
**Becky**, Thursday, October 10, 2013 at 12:30pmk = 0.693/t1/2

ln(No/N) = kt

No = 100

N = 65.7

k from above.

solve for t in years.

I found this equations, but my question is what is k?

- Chemistry -
**DrBob222**, Thursday, October 10, 2013 at 3:12pmk is from your first line. You know half-life is 4.5E9 yrs so you can calculate k.

N however is not 65.7 but 82.7

- Chemistry -
**Becky**, Thursday, October 10, 2013 at 5:28pmYes, I just copied the equation off of a different problem.

Thank you for your help!

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