# [SOLVED] simple word problem help

• Oct 23rd 2006, 12:58 PM
trapt2006@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 PM
Jameson
Simple interest is $P=P_0+P_0rt$

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

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

Can you take it from here?
• Oct 23rd 2006, 01:49 PM
Soroban
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 $x$ dollars at 5%.
. . This will earn: $5\% \times x \:=\:0.05x$ dollars in interest in one year.

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

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

and there is our equation!