Phy que 22. Pls answer

Solution:
Average life,

T_{a v} = \frac{T_{1 / 2}}{\ln 2} = \frac{1}{λ} According to question : \Rightarrow T_{a v} = \frac{1 - \ln 2}{x λ} \Rightarrow \frac{1}{λ} = \frac{1 - \ln 2}{x λ} \Rightarrow x = 1 - \ln 2 = 1 - 0.693 = 0.307