whatever% of anything is just (whatever/100) * anything.
so, 5000 at 3% will just be (3/100) * 5000, or 150 bucks.
now, if the two investments were to yield 275, we know the first yields 150, so the second investment must yield the difference, or 275 - 150, or 125.
so, what's the Principal to be invested for 1 year at 5% to get 125 bucks in interest from it?
[tex]\bf ~~~~~~ \textit{Simple Interest Earned}
\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$125\\
P=\textit{original amount deposited}\\
r=rate\to 5\%\to \frac{5}{100}\to &0.05\\
t=years\to &1
\end{cases}
\\\\\\
125=P(0.05)(1)\implies \cfrac{125}{(0.05)(1)}=P\implies 2500=P[/tex]
