Answer:
Nico invest $2500 at 9% interest rate and $800 at 4% interest rate.
Explanation:
He invests some money at 9%, and $1700 less than that amount at 4 %.
Let Nico invest $x at 9%.
It means he invest $( x-1700) at 4%.
The investments produced a total of $257 interest in 1 yr.
[tex]x\times \frac{9}{100}+(x-1700)\times \frac{4}{100}=257[/tex]
[tex]0.09x+(x-1700)0.04=257[/tex]
[tex]0.09x+0.04x-68=257[/tex]
[tex]0.13x-68=257[/tex]
Add 68 on both sides.
[tex]0.13x=257+68[/tex]
[tex]0.13x=325[/tex]
Divide both sides by 0.13.
[tex]x=2500[/tex]
Nico invest $2500 at 9% interest rate.
[tex]x-1700=2500-1700=800[/tex]
Nico invest $800 at 4% interest rate.
Therefore Nico invest $2500 at 9% interest rate and $800 at 4% interest rate.