Answer :
1) Age of Sea Shell : it contains 90% = 0.9
age = - T1/2 Ln 0.9 / Ln 2 = 846.66 years
2) age when C-14 was 99% : - T1/2 Ln 0.99 / Ln 2 = 80.76 yrs
Duration for C-14 content to diminish to 90% from 99% : 765.9 years
age = - T1/2 Ln 0.9 / Ln 2 = 846.66 years
2) age when C-14 was 99% : - T1/2 Ln 0.99 / Ln 2 = 80.76 yrs
Duration for C-14 content to diminish to 90% from 99% : 765.9 years