Respuesta :
Let x be the amount invest at 8%
Let y be the amount invest at 16%
Paul has $50,000 to invest:
[tex]x+y=50,000[/tex]His intent is to earn 13% interest on his investment. He can invest part of his money at 8% interest and part at 16% interest.
[tex]\begin{gathered} 50,000(0.13)=x(0.08)+y(0.16) \\ \\ 6,500=0.08x+0.16y \end{gathered}[/tex]Use the next system of equations to find x and y:
[tex]\begin{gathered} x+y=50,000 \\ 6,500=0.08x+0.16y \end{gathered}[/tex]1. Solve x in the first equation:
[tex]x=50,000-y[/tex]2. Substitute the x in the second equation by the value you get in the previous step:
[tex]6,500=0.08(50,000-y)+0.16y[/tex]3. Solve y:
[tex]\begin{gathered} 6,500=4,000-0.08y+0.16y \\ 6,500=4,000+0.08y \\ 6,500-4,000=0.08y \\ 2,500=0.08y \\ \frac{2,500}{0.08}=y \\ \\ y=31,250 \end{gathered}[/tex]4. Use the value of y to solve x:
[tex]\begin{gathered} x=50,000-y \\ x=50,000-31,250 \\ x=18,750 \end{gathered}[/tex]Solution for the system:
x=18,750
y=31,250
Answer: Paul needs to invers8% interest $18,75016% interest $31,250