c
\(T _{ x }= t ; T _{ y }=2 t\)

\(3 T _{ y }=6 t\)

\(N _{1}^{\prime}= N _{2}^{\prime}\)

\(N _{1} e ^{-\lambda_{1} 6 t }= N _{2} e ^{-\lambda_{2} 6 t }\)

\(\frac{ N _{1}}{ N _{2}}= e ^{\left(\lambda_{1}-\lambda_{2}\right) 6 t }= e ^{\ln 2\left(\frac{1}{t}-\frac{1}{2 t }\right) \times 6 t }= e ^{(1 n 2) \times 3}= e ^{ ln 8}=8\)

\(\frac{ N _{1}}{ N _{2}}=\frac{8}{1}\)