Let the amount paid at 12% be x
And the amount paid at 9% be y
then,
[tex]x+y=160000[/tex]and,
[tex](0.12)x+(0.09)y=17100[/tex]Now, let's solve this system of equations
1. Substitute x=17100-y
[tex]\begin{gathered} x=160000-y \\ 0.12\cdot(160000-y)+0.09y=17100 \end{gathered}[/tex]2. Simplify
[tex]\begin{gathered} 19200-0.12y+0.09y=171000 \\ 19200-0.03y=17100 \end{gathered}[/tex]3. solve for y
[tex]\begin{gathered} 19200-17100=0.03y \\ y=\frac{2100}{0.03} \\ y=70000 \end{gathered}[/tex]4. Calculate x
[tex]\begin{gathered} x+70000=160000 \\ x=160000-70000 \\ x=90000 \end{gathered}[/tex]So, the answer is
amount of 12% note is $90,000
amount of 9% note is $70,000