\(\frac{a}{3}=\frac{4b}{5},\frac{10b}{3}=\frac{5c}{2}\)
\(\Rightarrow\frac{a}{3}=\frac{b}{\frac{5}{4}},\frac{b}{\frac{3}{10}}=\frac{c}{\frac{2}{5}}\)
\(\Rightarrow\frac{a}{\frac{9}{10}}=\frac{b}{\frac{3}{8}},\frac{b}{\frac{3}{8}}=\frac{c}{\frac{1}{2}}\)
\(=>\frac{a}{\frac{9}{10}}=\frac{b}{\frac{3}{8}}=\frac{c}{\frac{1}{2}}\)
áp dụng t/c dãy tỉ số bằng nhau ta có:
\(\frac{a}{\frac{9}{10}}=\frac{b}{\frac{3}{8}}=\frac{c}{\frac{1}{2}}=\frac{a+b+c}{\frac{71}{40}}=\frac{142}{\frac{71}{40}}=80\)
\(\frac{a}{\frac{9}{10}}=80\Rightarrow a=72\)
\(\frac{b}{\frac{3}{8}}=80\Rightarrow b=30\)
\(\frac{c}{\frac{1}{2}}=80\Rightarrow c=40\)
vậy a=72,b=30,c=40
