# Thread: [SOLVED] simple word problem help

1. ## [SOLVED] simple word problem help

victor has invested $4000 into two accounts, part at 5% simple interest and part at 9% simple interest. Find how much he invested at each rate if the total interest after 1 year is$311.

2. Simple interest is $\displaystyle P=P_0+P_0rt$

So say $\displaystyle A=P_0+P_0(.05)(1)$ and $\displaystyle B=Q_0+Q_0(.09)(1)$. This describes the two investment conditions you listed.

Also we know that $\displaystyle Q_0+P_0=4000$ and $\displaystyle P_0(.05)(1)+Q_0(.09)(1)=311$

Can you take it from here?

3. Hello, trapt2006@sbcglobal.net!

Try some baby-talk . . .

Victor has invested $4000 into two accounts, part at 5% and part at 9%. Find how much he invested at each rate if the total interest after 1 year is$311.

He invested $\displaystyle x$ dollars at 5%.
. . This will earn: $\displaystyle 5\% \times x \:=\:0.05x$ dollars in interest in one year.

He invested the rest $\displaystyle (4000 - x)$ at 9%.
. . This will earn: $\displaystyle 9\% \times (4000 - x) \:=\:0.09(4000-x)$ dollars in interest in one year.

His total interest is $311: .$\displaystyle 0.05x + 0.09(4000 - x) \:=\:311\$

and there is our equation!