Posted by sam on .
A sample originally contained 2.5 g of rubidium 87 now contains 1.25 g. The half life of rubidium  87 is 6 x 10 ( to the 10th) years. How old is the sample? Is this possible? why or why not?

Science HELP 2nd question 
bobpursley,
See the other post. Same formula.

Science HELP 2nd question 
Joe,
6 x 10^10 years old b/c it's exactly half of 2.5, Not possible b/c world hasn't existed for 60 trillion years.