[tex]c_1=4\%=\frac4{100}=\frac2{50}=\frac1{25}\\m_r_1=4l\\\frac1{25}=\frac{m_s_1}{4}\\m_s_1=\frac{4}{25}\\\\c_2=2\%=\frac2{100}=\frac1{50}\\m_r_2=2l\\\frac1{50}=\frac{m_s_2}{2}\\m_s_2=\frac2{50}=\frac1{25}\\\\m_s_3=m_s_1+m_s_2\\m_s_3=\frac4{25}+\frac1{25}=\frac5{25}=\frac1{5}\\\\m_r_3=m_r_1+m_r_2\\m_r_3=4l+2l=6l\\\\C_3=\frac15:6*100\%\\C_3=\frac15*\frac16*100\%\\C_3=\frac1{30}*100\%=3,(3)\%[/tex]
