Solution:
According to the problem, let x the amount paid off at 11%. Then, we get the following equation:
[tex]0.11x+0.09(155000-x)=15550[/tex]now, applying the distributive property, this is equivalent to:
[tex]0.11x+13950-0.09x=15550[/tex]this is equivalent to:
[tex]0.02x\text{ = 15550-13950=1600}[/tex]that is:
[tex]0.02x=1\text{600}[/tex]solving for x, we get:
[tex]x\text{ = }\frac{1600}{0.02}=80000[/tex]then, we get:
[tex]80000\text{ at }11\%[/tex]and
[tex]155000-80000=\text{ 75000 at }9\%[/tex]so that, we can conclude that the correct answer is:
[tex]80000\text{ at }11\%[/tex]
and
[tex]\text{ 75000 at }9\%[/tex]