[tex]\it n:21=c\ rest\ 11 \Rightarrow n=21c+11\ \ \ \ \ (*)\\ \\ n=4 \stackrel{(*)}{\Longrightarrow} \ n=21\cdot4+11=84+11=95\ (nu \ \ convine)\\ \\ n=5 \stackrel{(*)}{\Longrightarrow} \ n=21\cdot5+11=105+11=116\ ( convine\ \c{s}i\ e\ cel\ mai\ mic)[/tex]
