Algebra 2
posted by chels .
half life carbon 14 is 5,730 years. If you start out 50 grams, how long will it take until it reaches 2 grams?

x = Xi e^kt
x/Xi = .5 = e^5730 k
ln .5 = 5730 k
.69315 = 5730 k
k = 1.21*10^4
x = Xi e^1.21*10^4 t
2 = 50 e^1.21*10^4 t
.04 = e^1.21*10^4 t
ln .04 = 1.21*10^4 t
3.22 = 1.21*10^4 t
2.66 * 10^4
= 26,600 years