please help
a hiker in africa discovers a skull that has 72 percent of its orignal amount of C-14

Question

please help 
a hiker in africa discovers a skull that has 72 percent of its orignal amount of C-14

phi · Answer

do you know the half-life of carbon-14 ?

erich · Answer

nope

phi · Answer

to do this problem, you need that info.  Is there more info on this question that you did not post?

erich · Answer

i only have like 2 questions left and i am done with the unit but i have to get them right

phi · Answer

you have not posted the full question

erich · Answer

k=0.0001

phi · Answer

what formula have you been studying ?
also, what units does "k" have ?   years ?  hours ?

erich · Answer

the formula is noe-kt

phi · Answer

do you mean
$$ N= N_0 e^{-kt} $$
?

erich · Answer

yes

phi · Answer

if you divide both sides by $N_0$
you can write that as
$$ \frac{N}{N_0} = e^{-kt}$$
N/N0 is a fraction, and in your problem, will be 0.72  (72% is 72/100 or 0.72)

I solve for t, using the numbers
$$ e^{-0.0001 t} = 0.72 $$

erich · Answer

so t = 0.72

phi · Answer

e^(-kt) is 0.72

to solve your equation, you should "take the log"  of both sides
can you do that ?

erich · Answer

idk how to do it man