You discovered a new radioactive isotope isotope and named it Geekonium-25.   At a.m., you have mg in your petrie  dish and at p.m., you measure only   mg.  What's the half-life? Work the problem on some paper... When you're done, click on the answer below. But, don't look at it before you've really tried it on your own! <<<  If you get really stuck, you can click on the hints below.  >>>