To answer this, you use the formula [tex]I = Prt[/tex] where
[tex]I[/tex] is the simple interest that builds
[tex]P[/tex] is the principal (AKA the amount invested/borrowed)
[tex]r[/tex] is the interest rate per year
[tex]t[/tex] is the lenght of the loan, in years.
In your situation:
[tex]\begin{aligned}I &= (\$3000)(5 \%/\text{year})(3 \text{ years})\\[0.5em]&= (3000)(0.05)(3)\\[0.5em]&= 450\end{aligned}[/tex]
This means there'd be $450 of simple interest due at the end of 3 years.
