Hey all. I'm tutoring a student right now on a subject I'm terrible in. It's modelling with exponential and log functions w/ radioactive decay. . . question to follow

Question

Hey all.   I'm tutoring a student right now on a subject I'm terrible in.  It's modelling with exponential and log functions w/ radioactive decay. . . question to follow

anonymous · Answer

The half life of radium 226 is 1600 years.  We have 22mg.  
a.  find a function that models the mass remaining after t years
b.  how much will remain after 4000 years?
c.  after how long will only 18 mg remain

Please give step by step.  I'm not sure how to explain this process.  Thanks!!!

anonymous · Answer

We understand that the general formula for halflife radioactive decay is m(t) = mnoughte^(-rt) where r = ln2/h

anonymous · Answer

mnought = 22 ND H = 1600

anonymous · Answer

alchemista, that's not super helpful :( but thanks for trying