# algebra

posted by .

The half-life of 234U, uranium-234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?

• algebra -

.5 = e^2.52*10^5 k
ln .5 = 2.52 * 10^5 k
k =-2.75*10^-6

ln .977 = -2.75*10^-6 t
t = 8460 years
= 8,000 years

• algebra -

.977=1e^(.693t/thalf)

take lne of each side.
ln.977=.692t/th

t= thalf*ln.977/.693

## Similar Questions

1. ### algebra

The half-life of 234U, uranium-234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed
2. ### algebra

The half-life of 234U, uranium-234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
3. ### algebra

The half-life of 234U, uranium-234, is 2.52 multiplied by 105 yr. If 98.8% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
4. ### algebra

The half-life of 234U, uranium-234, is 2.52 multiplied by 105 yr. If 98.8% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
5. ### algebra

The half-life of 234U, uranium-234, is 2.52 multiplied by 105 yr. If 98.6% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
6. ### math

The half-life of 234U, uranium-234, is 2.52 105 yr. If 97.4% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
7. ### algebra

The half-life of 234U, uranium-234, is 2.52 105 yr. If 98.4% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
8. ### math

The half-life of 234U, uranium-234, is 2.52 105 yr. If 98.3% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
9. ### pre algebra

The half-life of 234U, uranium-234, is 2.52 105 yr. If 98.6% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?
10. ### ALGEBRA

The half-life of 234U, uranium-234, is 2.52 multiplied by 105 yr. If 98.3% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed?

More Similar Questions