18. a) [latex] frac{2}{3}: frac{5}{6} = frac{2}{3} * frac{6}{5} = frac{4}{5} [/latex] b)[latex]2: frac{1}{4}= frac{2}{1}* frac{4}{1}=8 [/latex] c) [latex] frac{7}{9} : 3= frac{7}{9} * frac{1}{3}= frac{7}{27} [/latex] 19. a) [latex] frac{2}{3}[/latex] masy 12kg [latex] frac{2}{3} * frac{12}{1}= frac{8}{1}= 8 [/latex] kg b) [latex] frac{3}{4} [/latex] kwoty 60 zł [latex] frac{3}{4} * frac{60}{1}= 45[/latex] zł c) [latex] frac{4}{5} [/latex] objętości 25 litrów [latex] frac{4}{5} * frac{25}{1}= 20 [/latex] litrów 20. a) [latex] frac{3}{8} * frac{28}{1}= frac{21}{2} = 10 frac{1}{2} [/latex] b) [latex] frac{2}{3} * 3 frac{3}{4} = frac{2}{3} * frac{15}{4}= frac{5}{2} = 2 frac{1}{2} [/latex] c) [latex]1 frac{1}{6} *2 frac{1}{7} = frac{7}{6}* frac{15}{7}= frac{5}{2}= 2 frac{1}{2} [/latex]
