Question

A radioactive substance decays exponentially. A scientist begins with 190 milligrams of a radioactive

Answer 1

Answer: 65.1 (mg)

Step-by-step explanation:

$y=190*e^{-a*t}\\\\Calculate\ a:\\\\t=33,y=95(mg)\\\\190*e^{-a*33}=95\\\\e^{-a*33}=0.5\\\\-a*33=ln(0.5)\\\\a=\dfrac{ln(\dfrac{1}{2}) }{-33} \\\\a=0,02100... \approx{0.021}\\\\If\ t=51\ h, y=190*e^{-0.02100*51}=65.09167...\approx{65.1}$