An initial sample of iridium-192 is prepared pure, with no contamination of other isotopes. After a certain amount of time, one finds that the sample includes 4.4% osmium-192. How much times has passed since the initial sample was prepared? (Hint: Use what you know about half life to create a proportion. 50% of the sample would decay in one half life, so how long would it take for 4.4% o the sample to decay?)