\(\frac{\overline{15abc}}{\overline{abc0}}=\frac{15000}{\overline{abc0}}+\frac{\overline{abc}}{\overline{abco}}=\frac{1500}{\overline{abc}}+\frac{\overline{abc}}{\overline{abc0}}=12,1\)
\(\Rightarrow\frac{1500}{\overline{abc}}+0,1=12,1\Rightarrow\frac{1500}{\overline{abc}}=12\Rightarrow\overline{abc}=1500:12=125\)