he half-life of 234U, uranium-234, is 2.52 multiplied by 105 yr. If 97.5% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
yr
the fraction after t years is
(1/2)^(t/252000) so, solve for t in
.975 = (1/2)^(t/252000)
t = 9204 years