calculus
posted by jessica .
In the early 1960s, radioactive strontium90 was released during atmospheric testing of nuclear weapons and got into the bones of people alive at the time. If the halflife of strontium90 is 27 years, what fraction of the strontium90 absorbed in 1962 remained in people's bones in 1994?

19941962 = 32 years
A = Ao*2^t/27, so
A/Ao = 2^32/27 = .4397 = 43.97%