10. Consider two atoms of a radioactive isotope Cesium-137 (half-life = 30 years). Neither atom has yet decayed. One Cesium-137 atom was created in a radioactive decay of a more massive element 30 years ago. The other Cesium-137 atom was created in a nuclear reactor 15 years ago. Compare the likelihood of the older atom decaying sometime in the next 30 years with the likelihood of the younger atom decaying sometime in the next 30 years.