I simply can’t figure it out I need help finding a different way of solving this problem

Question

The radioactive element carbon 14 has a half-life of 5750 years the scientist determined that the bones from a mastodon Had lost 66.6% of the carbon 14 how old were the bones at the time they were discover

Answer 1

1/2 = e^5750r where 5750 years = half time (as marching bands come out after 1st half of the football game)

take natural logs of both sides to get:

ln.5 = 5750r, solve for r, divide both sides by 5750

r = (ln.5)/5750 = annual rate of decay = about - 0.127 %

if about 2/3 is left, that's more than 1/2 so not as old as 5750 years old

.666 = 66.6%

.666 = e^(ln.5)/5750)t take natural logs of both sides

ln.666 = (ln.5/570)t divide both sides by (ln.5)/5750

t = 5750(ln.666)/ln.5 = about 3372 years old, rounded to nearest integer

a calculator with ln and exponential functions is very useful