\frac{6}{15}= \frac{2}{5}\\\\\\b). \ \ \frac{3}{5}= \frac{24}{40}> \frac{21}{40}\\\\\\ {} \ \ \ \ \ \frac{1}{17}= \frac{3}{51}\\ \\\\{} \ \ \ \ \ \ \frac{3}{8}= \frac{9}{24}< \frac{20}{24}= \frac{5}{6}" alt="\displaystyle \tt a). \ \ \frac{1}{5}= \frac{2}{10}< \frac{3}{10}\\ \\\\{} \ \ \ \ \ \ \frac{1}{2}= \frac{2}{4}< \frac{3}{4}\\\\\\{} \ \ \ \ \ \frac{7}{15}> \frac{6}{15}= \frac{2}{5}\\\\\\b). \ \ \frac{3}{5}= \frac{24}{40}> \frac{21}{40}\\\\\\ {} \ \ \ \ \ \frac{1}{17}= \frac{3}{51}\\ \\\\{} \ \ \ \ \ \ \frac{3}{8}= \frac{9}{24}< \frac{20}{24}= \frac{5}{6}" align="absmiddle" class="latex-formula">
\frac{49}{70}=0,7" alt="\displaystyle \tt c). \ \ \frac{5}{6}= \frac{30}{36}< \frac{32}{36}= \frac{8}{9}\\ \\\\{} \ \ \ \ \ \frac{1}{12}= \frac{5}{60}< \frac{9}{60}= \frac{3}{20}\\ \\\\{} \ \ \ \ \ \ \frac{5}{7}= \frac{50}{70}> \frac{49}{70}=0,7" align="absmiddle" class="latex-formula">