In $\triangle ABC$, $DE \parallel BC$. If $AD = 4$, $DB = 2$, $AE = 6$, then $EC = ?$

Since $DE\parallel BC$, $\frac{AD}{DB}=\frac{AE}{EC}$, so $\frac{4}{2}=\frac{6}{EC}$. Solving gives $EC=\frac{6\times 2}{4}=3$.