SOLUTION: A person invests a total of R200 000 in money-market accounts at three different banks: Bank A pays 6% interest per year on a low risk investment, Bank B pays 6,5% per year on a

Algebra ->  Matrices-and-determiminant -> SOLUTION: A person invests a total of R200 000 in money-market accounts at three different banks: Bank A pays 6% interest per year on a low risk investment, Bank B pays 6,5% per year on a      Log On


   



Question 1110205: A person
invests a total of R200 000 in money-market accounts at three different banks: Bank A pays 6% interest
per year on a low risk investment, Bank B pays 6,5% per year on a medium risk investment and Bank
C pays 8% per year on a high risk investment. Suppose the person invests two times the amount of
Bank A at Bank B, and the total interest earned after one year is R14 000. Compose three independent
equations and use reduction of a 3×3 matrix to determine how much was invested at each bank.

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
x=amount at A
2x=amount at B
200,000-3x=amount at C, everything left after A and B.
.06x+.065(2x)+.08(200000-3x)=14000
.19x-.24x+16000=14000
-.05x=-2000
x=40000@ 6%=2400 at A
2x=80000@6.5%=5200 at B
200000-3x=80000@8%=6400 at C
adds to 14,000