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P. 4579. Traces of Argon were found in one of the most ancient stone of the Earth. The stone was powdered in vacuum, and it was found that the number of Argon atoms is 1/10000 of the number of Potassium atoms. The atoms are radioactive and their half-life is 1.18.109 years. 11% of the daughter elements are atoms which are stable. Now 0.0118% of all the potassium atoms is isotopes. How old is the stone?

(5 points)

Deadline expired on 10 December 2013.

Google Translation (Sorry, the solution is published in Hungarian only.)

Megoldásvázlat. 3,68 milliárd éves.

Statistics on problem P. 4579.
 75 students sent a solution. 5 points: 58 students. 4 points: 12 students. 3 points: 1 student. 1 point: 2 students. Unfair, not evaluated: 2 solutions.

• Problems in Physics of KöMaL, November 2013

•  Támogatóink: Morgan Stanley