a)
[tex]\frac{2}{5} \ z \ 7,5=\frac{2}{5}\cdot7\frac{5}{10}=\frac{2}{5}\cdot7\frac{1}{2}=\frac{2}{5}\cdot\frac{15}{2}=\frac{30}{10}=\boxed3\\[/tex]
Odp. 2/5 liczby 7,5 to 3.
b)
[tex]\frac{3}{4} \ z \ 20,4=\frac{3}{4}\cdot20\frac{4}{10}=\frac{3}{4}\cdot20\frac{2}{5}=\frac{3}{4}\cdot\frac{102}{5}=\frac{3}{2}\cdot\frac{51}{5}=\frac{153}{10}=\boxed{15\frac{3}{10}}\\[/tex]
Odp. 3/4 z 20,4 to 15 i 3/10.
