Question 154765
not sure about your formula...


for half-life calculations, you are right - there is a 1/2 in the formula


A=Ao*(1/2)^(t/h)


A is the current amount, Ao is the starting amount, t is the time, h is the half-life


to find the time __ divide by Ao __ A/Ao=.5^(t/h) __ take log __ ln(A/Ao)=(t/h)ln(.5)


divide by ln(.5) __ [ln(A/Ao)]/[ln(.5)]=t/h __ multiply by h __ h{[ln(A/Ao)]/[ln(.5)]}=t



5730[ln(.995)/ln(.5)]=t __ 41.4=t (approx) __ doesn't seem old enough