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.

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- Oct 23rd 2006, 12:58 PMtrapt2006@sbcglobal.net[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.

- Oct 23rd 2006, 01:07 PMJameson
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? - Oct 23rd 2006, 01:49 PMSoroban
Hello, trapt2006@sbcglobal.net!

Try some baby-talk . . .

Quote:

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!