I have two half-life problems that I have the answers for, but don't know how to solve. Please explain, Thanks! 
1. If the half-life of Palladium 100 is 3.63 days, what percentage of the original amount is left after 3 weeks?
Answer: 1.81%
2. An unknown radioactive element is found to decay such that only 2% remains after 6 hrs. What is the unknown element's half-life?
Answer: 1.06 hrs
1. If the half-life of Palladium 100 is 3.63 days, what percentage of the original amount is left after 3 weeks?
Answer: 1.81%
2. An unknown radioactive element is found to decay such that only 2% remains after 6 hrs. What is the unknown element's half-life?
Answer: 1.06 hrs