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October 20, 2014

October 20, 2014

Posted by **Star** on Wednesday, November 15, 2006 at 10:57pm.

Assume we start with 100 atoms Rb87 @ t=0 when the fossil just started to form. Then after some time, y will have disintegrated and formed Sr87. Thus 100-y will be the number of Rb87 atoms left.

(Sr87/Rb87)=0.090 from the problem.

y/(100-y)=0.090

Solve for y and 100-y

k = 0.693/t

ln(N

N

N = 100 - y from above.

k = from above

solve for t, the age of the fossil.

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