a
\( {\text{N}} = \frac{{{{\text{N}}_{\text{0}}}}}{{{{\text{2}}^{\frac{{\text{t}}}{{{{\text{t}}_{{\text{1/2}}}}}}}}}}\,\,\)

\(\Rightarrow \,\,\,\frac{{{N_1}}}{{{N_2}}} = \frac{{{N_{{0_1}}}{2^{\frac{t}{{({t_{1/2{)_1}}}}}}}}}{{{N_{{0_2}}}{2^{\frac{1}{{{{({t_{1/2}})}_2}}}}}}}\)

\(\frac{{{N_1}}}{{{N_2}}} = \frac{2}{1}\frac{{{2^{\frac{1}{{16}}}}}}{{{N_{{0_2}}}{2^{\frac{t}{{12}}}}}} = 2\frac{{{2^{\frac{{48}}{{16}}}}}}{{{2^{\frac{{48}}{{12}}}}}}\,\,\,\,\,\,\,\)

\(\therefore \,\,\,\frac{{{N_1}}}{{{N_2}}} = (2)\frac{{{2^3}}}{{{2^4}}} = \frac{1}{1}\)