\(3 \frac{1}{12} + 4 \frac{11}{15} + 1 \frac{3}{5} = 3 \frac{5}{60} + 4 \frac{44}{60} + 1 \frac{36}{60} = 8 \frac{85}{60} = 9 \frac{25}{60} = 9 \frac{5}{12}\) т
Ответ: \(9 \frac{5}{12}\) т.
\(4 \frac{11}{20} + 1 \frac{3}{5} = 4 \frac{11}{20} + 1 \frac{12}{20} = 5 \frac{23}{20} = 6 \frac{3}{20}\) л
\(4 \frac{11}{20} - \frac{17}{20} = 3 \frac{31}{20} - \frac{17}{20} = 3 \frac{14}{20} = 3 \frac{7}{10}\) л
\(4 \frac{11}{20} + 6 \frac{3}{20} + 3 \frac{7}{10} = 4 \frac{11}{20} + 6 \frac{3}{20} + 3 \frac{14}{20} = 13 \frac{28}{20} = 14 \frac{8}{20} = 14 \frac{2}{5}\) л
Ответ: \(14 \frac{2}{5}\) л.
\(6 \frac{3}{4} - 2 \frac{19}{20} = 6 \frac{15}{20} - 2 \frac{19}{20} = 5 \frac{35}{20} - 2 \frac{19}{20} = 3 \frac{16}{20} = 3 \frac{4}{5}\) сотен рублей
\(6 \frac{3}{4} + 1 \frac{9}{20} = 6 \frac{15}{20} + 1 \frac{9}{20} = 7 \frac{24}{20} = 8 \frac{4}{20} = 8 \frac{1}{5}\) сотен рублей
\(6 \frac{3}{4} + 3 \frac{4}{5} + 8 \frac{1}{5} = 6 \frac{15}{20} + 3 \frac{16}{20} + 8 \frac{4}{20} = 17 \frac{35}{20} = 18 \frac{15}{20} = 18 \frac{3}{4}\) сотен рублей
Ответ: \(18 \frac{3}{4}\) сотен рублей.