Answer
$4.75\%$
Work Step by Step
He invested two amounts at two different interest rates that we do not know.: $1000$ dollars at $x$ interest rate and $2000$ dollars at $ 1.5x$ (half percent higher interest rate), we know that he will receive $190$ dollars total interest. We determine $x$: $$\begin{aligned}
1000x +2000(1.5x)&=190\\
1000x + 3000x&=190\\
4000x&=190\\
x&=0.0475\\
&=4.75\%
\end{aligned}$$
