SOLUTION: The radioisotope Cobalt-60 is used in cancer therapy. The half-life of this isotope is 5.27 years. Which equation determines the percent of an initial amount of the isotope rema

Algebra ->  Real-numbers -> SOLUTION: The radioisotope Cobalt-60 is used in cancer therapy. The half-life of this isotope is 5.27 years. Which equation determines the percent of an initial amount of the isotope rema      Log On


   

Question 1105048: The radioisotope Cobalt-60 is used in cancer therapy. The half-life of this isotope is 5.27 years.
Which equation determines the percent of an initial amount of the isotope remaining after t years?

Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
y=pe%5E%28-kt%29
ln%28y%29=ln%28p%29-kt
ln%28y%29-ln%28p%29=-kt
k=%28ln%28y%29-ln%28p%29%29%2F%28-t%29
k=%28ln%28p%29-ln%28y%29%29%2Ft
k=ln%28p%2Fy%29%2Ft


Half Life 5.27 years, p%2Fy=1%2F%281%2F2%29=2;
highlight_green%28k=ln%282%29%2F5.27%29

k=0.13153

highlight_green%28y=p%2Ae%5E%28-0.13153t%29%29
p is initial amount.
y is not the percent remaining, but the AMOUNT remaining.