Ответ:

[tex]11 \frac{3}{5} + 9 \frac{5}{20} + 10 \frac{45}{40} [/tex]

[tex]11 \frac{3}{5} = 11 \frac{24}{40} [/tex]

[tex]9 \frac{5}{20} = 9 \frac{10}{40} [/tex]

[tex]11 \frac{24}{40} + 9 \frac{10}{40} + 10 \frac{45}{40} = 30 \frac{79}{40} = 31 \frac{39}{40} [/tex]