Answer:
Amount invested at 5% = $9,000
Amount invested at 8% = $9,000
Explanation:
Let the amount of the 5% investment be x.
So the amount of the 8% investment will be (18000 - x)
If he earned $1170 interest after 1 year, we can go ahead and determine the value of x by setting up the below equation;
[tex]0.05\cdot x+0.08\cdot(18000-x)=1170[/tex]If we expand the parentheses, we'll have;
[tex]\begin{gathered} 0.05x+1440-0.08x=1170 \\ -0.03x+1440=1170 \end{gathered}[/tex]Let's subtract 1140 from both sides of the equation;
[tex]\begin{gathered} -0.03x=1170-1440 \\ -0.03x=-270 \\ \end{gathered}[/tex]Let's divide both sides by -0.03;
[tex]\begin{gathered} \frac{-0.03x}{-0.03}=\frac{-270}{-0.03} \\ x=9000 \end{gathered}[/tex]We can see that Mr. Jones invested $9,000 at 5%.
So the amount he invested at 8% will be;
[tex]18000-x=18000-9000=9000[/tex]We can also see that the amount invested at 8% was $9,000
