(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Hei!Half life of the reaction is about 1,25 billion years. Assuming that the age of earth is 5 billion years,the concentration of K on earth since its formation decreased:

a)2times b)4times c)8 times d)16times

3. The attempt at a solution

So I just do like that T[itex]\underline{}1/2[/itex]=1,25 bilion years

age=5 bilion years

so in the begining we have X and then it is X/2 so we 1,25 bilion year

then X/4 it is 2,5 bilion year and then X/8 so it is 5 bilion years

so the answer i think is it decreased 8 times

but my question is: is there easier way to do it?

thanks in advance!

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# Homework Help: Half life of K

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