SOLUTION: If 100 grams of a radioactive material diminish to 80 grams in 2 years, find the half life of the substance: If 100 grams of a radioactive material diminish to 80 grams in 2 years,

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: If 100 grams of a radioactive material diminish to 80 grams in 2 years, find the half life of the substance: If 100 grams of a radioactive material diminish to 80 grams in 2 years,      Log On


   

Question 134084: If 100 grams of a radioactive material diminish to 80 grams in 2 years, find the half life of the substance: If 100 grams of a radioactive material diminish to 80 grams in 2 years, find the half life of the substance
The answer is actually 6.21 years how do I get this answer?
Answer by Ganesha(13) About Me  (Show Source):
You can put this solution on YOUR website!
decay = .8 in 2year.
Solve for .8^(x/2) =.5
x/2 = log.5/log.8
x=2log.5/log.8 =6.212567439