Technetium-99m is an ideal radioisotope for scanning organs because it has a half-life of 6.0 {\rm hr} and is a pure gamma emitter. Suppose that 280{\rm mg} were prepared in the technetium generator this morning. How many milligrams would remain after the following intervals?

Answer 1

You still gave no intervals; however, look at your earlier post. I showed you how to do it there.