SOLVING:
[tex]\begin{cases}&x+y=40\quad\Longrightarrow\ Equation\ 1\\&0.08x+0.03y=1.7\quad\Longrightarrow\ Equation\ 2\end{cases}\\ \\ \\y=40-x\\ \\\textbf{Replace\ "y"\ in\ equation\ 2:}\\ \\0.08x+0.03(40-x)=1.7\\ \\0.08x+1.2-0.03x=1.7\\ \\0.05x+1.2=1.7\\ \\0.05x=1.7-1.2\\ \\0.05x=0.5\\ \\x= \dfrac{0.5}{0.05}\\ \\x=10\quad\to\boxed{\boxed{\spadesuit\ First\ answer.\ \spadesuit}}\\ \\ \\y=40-10\\ \\y=30\quad\to\boxed{\boxed{\spadesuit\ Second\ answer.\ \spadesuit}}[/tex]
[tex]\textbf{Testing\ in\ first\ equation:}\\10+30=40\\40=40\ \checkmark\\ \\\textbf{Testing\ in\ second\ equation:}\\0.08(10)+0.03(30)=1.7\\0.8+0.9=1.7\\1.7=1.7\ \checkmark\\ \\\textbf{HOPE\ THIS\ HELPS...!!}[/tex]
