1.
[tex] \frac{a}{b} + \frac{c}{d} = \frac{78 \times 15 + 8}{15} = \frac{1178}{15} [/tex]
[tex] \frac{a}{b} = \frac{12 \times 30 + 7}{30} = \frac{19}{1} = \frac{19 \times 15}{15} = \frac{285}{15} [/tex]
[tex] \frac{c}{d} = \frac{1178 - 285}{15} = \frac{893}{15} [/tex]
2.
[tex] \frac{a}{b} + \frac{2}{5} = \frac{11}{15} = > \frac{a}{b} = \frac{11 - 6}{15} = \frac{5}{15} [/tex]
3.
[tex]( \frac{5}{2} + \frac{11}{8} ) - ( \frac{5}{2} - \frac{11}{8} ) = \frac{31}{8} - \frac{9}{8} = \frac{22}{8} [/tex]
