The spear is 4620 years old.
N=N0e^-kt
N0 = initial amount of C-14 (at time t = 0)
N = amount of C-14 at time t
t = time, in years
k = 0.0001
N/N0 = e^-kt
we know N/N0 is 0.63
so we have:
0.63 = e^-kt
we can take the ln of both sides, leaving us with:
ln0.63 = -kt
t = ln0.63 / -(0.0001)
t = 4620 years
hope this helps with your thing!
-keynerd23
