Activity of radioactive element decreased to one third of original activity `R_0` in `9` years. After further `9` years, its activity will be

The activity of a radioactive element decreases in 10 years to 1/5 of initial activity A_(0) . After further next 10 years, its activity will be

The activity of a radioactive element decreases in 10 years to 1/5 of initial activity A_(0) . After further next 10 years, its activity will be

The activity of a radioactive element decreases to one third of the original activity I_(0) in a period of nine years. After a further lapse of nine years, its activity will be

The activity of a radioative element decreases to one third of the original activity I_(0) in a period of nine years. After a further 1apse of nine years, its activity will be

The activity of a radioative element decreases to one third of the original activity I_(0) in a period of nine years. After a further 1apse of nine years, its activity will be

The activity of a radioactive sample decreases to 1//3 of the original activity, A_(0) in a period of 9 years. After 9 years more, its activity A_(0)//x . Find the value of x .