SOLUTION: Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9% simple interest. In one year Robert earns $660 in interest. How much did he invest at each amo

SOLUTION: Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9% simple interest. In one year Robert earns $660 in interest. How much did he invest at each amo

Algebra.Com

Question 225538: Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9% simple interest. In one year Robert earns $660 in interest. How much did he invest at each amount?
Answer by rfer(16322) (Show Source): You can put this solution on YOUR website!
.07x+.09(8000-x)=660
.07x+720-.09x=660
-.02x=-60
x=$3000 at 7%
8000-3000=$5000 at 9%
RELATED QUESTIONS
Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9%... (answered by solver91311)

Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9%... (answered by rfer)

Robert invests $8000 in a bank. Part is invested at 7% simple interest and part at 9%... (answered by checkley77)

A person invests $8000 for one year. Part of this amount is invested at 2.65% simple... (answered by stanbon)

Fran received $113 per year in simple interest from investing $1300.00 Part is invested... (answered by josmiceli)

A teacher invests $12,000 in accounts and earns $$870 in interest for the year. Part of... (answered by greenestamps)

Lon Triah invested $5000 at a local bank. Part was invested at 6% simple interest and the (answered by ikleyn)

Marissa invested $7000 for 1 year. Part was invested at 4% simple interest and part... (answered by checkley79)

Fran receives $153 per year in simple interest from investing $1900. Part is invested at... (answered by TimothyLamb)