Question

ofer coroana! URGENT​

Answer 1

$\displaystyle a)~\frac{1,2}{7n} =\frac{0,6}{3,5} \Rightarrow \frac{\cfrac{12}{10} }{7n} =\frac{\cfrac{6}{10} }{\cfrac{35}{10} } \Rightarrow \frac{12}{10} \cdot \frac{1}{7n} =\frac{6}{10} \cdot \frac{10}{35} \Rightarrow \frac{12}{70n} =\frac{6}{35} \Rightarrow \\\\ \Rightarrow 12 \cdot 35=6 \cdot 70n \Rightarrow 420=420n \Rightarrow n=\frac{420}{420} \Rightarrow n=1$

$\displaystyle b)~\frac{6n}{2,5} =\frac{8}{0,(6)} \Rightarrow \frac{6n}{\cfrac{25}{10} }=\frac{8}{\cfrac{6}{9} } \Rightarrow 6n \cdot \frac{10}{25} =8 \cdot \frac{9}{6} \Rightarrow \frac{60n}{25} =\frac{72}{6} \Rightarrow \frac{12n}{5} =12\Rightarrow \\\\ \Rightarrow 12n =12 \cdot 5 \Rightarrow 12n=60 \Rightarrow n=\frac{60}{12} \Rightarrow n=5$

$\displaystyle c)~\frac{3,6}{4,5} =\frac{2n}{7,5}\Rightarrow \frac{\cfrac{36}{10} }{\cfrac{45}{10} }=\frac{2n}{\cfrac{75}{10} }\Rightarrow \frac{36}{10} \cdot \frac{10}{45} =2n \cdot \frac{10}{75} \Rightarrow \frac{36}{45} =\frac{20n}{75} \Rightarrow \\\\ \Rightarrow 36 \cdot 75=20n \cdot 45 \Rightarrow 2700=900n \Rightarrow n=\frac{2700}{900} \Rightarrow n=3$

$\displaystyle d)~\frac{0,3}{2,4} =\frac{1,5}{3n} \Rightarrow \frac{\cfrac{3}{10} }{\cfrac{24}{10} } =\frac{\cfrac{15}{10} }{3n} \Rightarrow \frac{3}{10} \cdot \frac{10}{24} =\frac{15}{10} \cdot \frac{1}{3n} \Rightarrow \frac{3}{24} =\frac{15}{30n} \Rightarrow \\\\ \Rightarrow 3 \cdot 30n=15 \cdot 24 \Rightarrow 90n=360 \Rightarrow n=\frac{360}{90}\Rightarrow n= 4$