Răspuns:
Explicație pas cu pas:
a)
[tex]\bf \dfrac{a}{b} =\dfrac{2}{5}\Rightarrow 5\cdot a = 2\cdot b\Rightarrow \boxed{ \bf a = \dfrac{2b}{5} }[/tex]
[tex]\text{\bf Aflam cat la suta reprezinta numarul ~a ~din ~b}[/tex]
[tex]\bf a = \dfrac{a}{b} \cdot 100[/tex]
[tex]\bf a = \dfrac{2b}{5}[/tex]
[tex]\bf a= \dfrac{~\dfrac{2b}{5}~}{b} \cdot 100=\dfrac{2b}{5}:b \cdot 100=\dfrac{2\not b}{5}\cdot\dfrac{1}{\not b} \cdot 100=\dfrac{200}{5} =40\Rightarrow[/tex]
[tex]\red{\boxed{\bf 40\% ~~reprezinta~~a~~din~ ~b}}[/tex]
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b)
[tex]\bf \dfrac{a}{6} =\dfrac{b}{25}\Rightarrow 25\cdot a = 6\cdot b\Rightarrow \boxed{ \bf a = \dfrac{6b}{25} }[/tex]
[tex]\text{\bf Aflam cat la suta reprezinta numarul ~a ~din ~b}[/tex]
[tex]\bf a = \dfrac{a}{b} \cdot 100[/tex]
[tex]\bf a = \dfrac{6b}{25}[/tex]
[tex]\bf a= \dfrac{~\dfrac{6b}{25}~}{b} \cdot 100=\dfrac{6b}{25}:b \cdot 100=\dfrac{6\not b}{25}\cdot\dfrac{1}{\not b} \cdot 100=\dfrac{600}{25} =24\Rightarrow[/tex]
[tex]\purple{\boxed{\bf 24\% ~~reprezinta~~a~~din~ ~b}}[/tex]
-------------------pav38--------------------------
c)
[tex]\bf \dfrac{8}{b} =\dfrac{3}{a}\Rightarrow 8\cdot a = 3\cdot b\Rightarrow \boxed{ \bf a = \dfrac{3b}{8} }[/tex]
[tex]\text{\bf Aflam cat la suta reprezinta numarul ~a ~din ~b}[/tex]
[tex]\bf a = \dfrac{a}{b} \cdot 100[/tex]
[tex]\bf a = \dfrac{3b}{8}[/tex]
[tex]\bf a= \dfrac{~\dfrac{3b}{8}~}{b} \cdot 100=\dfrac{3b}{8}:b \cdot 100=\dfrac{3\not b}{8}\cdot\dfrac{1}{\not b} \cdot 100=\dfrac{300}{8}\Rightarrow[/tex]
[tex]\pink{\boxed{\bf 37,5\% ~~reprezinta~~a~~din~ ~b}}[/tex]
Sper să fie de folos răspunsul meu chiar dacă vine cu 3 zile întârziere față de când ai postat exercițiul.
Baftă multă !
