In 1976 a research hospital bought half a gram of radium for cancer research. Assuming the hospital is still exists, how much of this radium will the hospital have in the year 6836 if the half-life of radium is 1620 years?

Answer 1

This this is a "half-life" situation we can use (1/2) as a base
amount = .5(1/2)^(t/1620)
if 1976--- t = 0, then 6836 ---> t = 4860

amount = .5(.5)^(4860/1620)
= .5(.5)^3 = .5^4 = .0625

.0625 g will be left