\(\frac{1}{2}a=\frac{2}{3}b\Rightarrow\frac{a}{\frac{2}{3}}=\frac{b}{\frac{1}{2}}\Rightarrow a=\frac{b}{\frac{3}{4}}\)
\(\Rightarrow\frac{a}{1}=\frac{b}{\frac{3}{4}}=\frac{c}{\frac{2}{3}}\)
Áp dụng tính chât dãy tỉ số bằng nhau ta có
\(\frac{a}{1}=\frac{b}{\frac{3}{4}}=\frac{c}{\frac{2}{3}}=\frac{a-b}{1-\frac{3}{4}}=\frac{15}{\frac{1}{4}}=60\)
\(\Rightarrow a=60.1=60\)
\(b=60.\frac{3}{4}=45\)
\(c=60.\frac{2}{3}=40\)