The half life of a radioactive isotope 'X' is 20 years. It

Last updated: 7/31/2022

The half life of a radioactive isotope 'X' is 20 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio 1:7 in a sample of a given rock. The age of the rock is estimated to be A 40 years B 60 years C 80 years D 100 years