Please look at the attached file. The first part of the question: why it doesn't decay to the GS. I think thats simply because the nuclear spin changes by 4 and therefore this decay is very supressed. But how "is it possible for the isomeric state at 140kev which decays by gamma emisson, to have a half life of several hours." (ie. a half life comparable to the original state (Mo) decaying to the allowed excited of Tc. Any tips on what approach I can take to show this? Thanks.