Question 249949: Write a system of equations that could be used to solve the following problem. express each of the systems in standard form. Use the inverse matrix method to solve with a calculator. Paula invested $6,500 in three different bank accounts for one year. One account earned 5% interest for the year, and the other two accounts earned 8% and 10% respectively. the total interest earned for the three investments was $560 for the year. If the sum of the 5% and 8% investments was $500 less than the 10% investment, find the amount invested in each account.
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! I did NOT use the inverse matrix method but all the info and equations you need should be here.
I=Prt
P=6500
I=560
t=1
r1=5%
r2=8%
r3=10%
P1+P2=P3-500
6500=P3-500+P3
3500=P3
P1+P2=3000
I=Prt
I3=3500*.10*1=350
I1+I2=560-350=210
.05 (P1)+.08(3000-P1)=210
1000=P1
P2=3000-P1=2000
so we have
P1=1000
P2=2000
P3=3500
r1=5%
r2=8%
r3=10%
I1+I2=210
I3=350
I1 can be found by I=Prt
I2 can be found by I=Prt or 210-I1
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