SOLUTION: By measuring the decay of radioactive carbon-14, scientists can estimate the age of the remains of living things. Carbon-14 decays at a rate of 0.0121% per year (or retains 99.98

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: By measuring the decay of radioactive carbon-14, scientists can estimate the age of the remains of living things. Carbon-14 decays at a rate of 0.0121% per year (or retains 99.98      Log On


   

Question 635464: By measuring the decay of radioactive carbon-14, scientists can
estimate the age of the remains of living things. Carbon-14 decays at
a rate of 0.0121% per year (or retains 99.9879% of its radioactivity).
a. Write a rule for the function that gives the amount of a 5-mg lab
sample remaining t years after its mass is first measured.
b. Find the half-life of carbon-14.
Thank you so much! Also, thank you for your time in helping me!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

 Q%28t%29+=+5e%5E%28.0121t%29

Find the half-life of carbon-14. 

    2+=+e%5E%28.0121t%29

   ln(2)/.0121 = t = 57.2849 yrs

the 'ln' function is on scientific calculators

 ln(2) being a symbol for 

Using a caculator, this is the quickest way to do decay problems

 enter 2, hit ln and then / .0121