Here, T=1500yrs, t=?
`N/(N_0)=(10^-2g)/(1g)=10^-2=(1/2)^n=1/100`
`:. n=(log1-log2)=log1-log100`
`n(0-0.3010)=0-2, n=2/0.3010=6.6445`
As `n=t/T`
`:. t=nT=6.6445xx1500=9967years.`
(ii) `N/(N_0)=(1-10^(-3))/1=0.999=(1/2)^n`
`:. n(log_e1-log_e2)=log_e0.999`
or `n(0-0.6931)=-1.0005`,
`n=1.0005/0.6931=1.4435`
As `n=t/T :. t=nT=1.4435xx1500yrs`
`=2165.2 years`