SOLUTION: Nina invested 10,000 dollars. She put one part in certificates of deposit that paid 3% annual interest and the rest into a money market account that paid 5% annual interest. The in

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Nina invested 10,000 dollars. She put one part in certificates of deposit that paid 3% annual interest and the rest into a money market account that paid 5% annual interest. The in      Log On


   

Question 911450: Nina invested 10,000 dollars. She put one part in certificates of deposit that paid 3% annual interest and the rest into a money market account that paid 5% annual interest. The interest for one year totaled 380 dollars. How much money did she invest in a money market account.
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
Total amount of money invested: $10000
x+y=10000,
Total yearly interest for the two accounts is: $380
0.03*x+0.05*y=380
x=10000-y
Substitute for x
0.03*(10000-y)+0.05*y=380
Multiply out
300-0.03*y+0.05*y=380
Combine like terms.
0.02*y=80
Isolate y
y=$ 4000.00 at 5% earns $200 interest money market
x=10000-y
Calculate x
x=$ 6000.00 at 3% earns $180 interest
Check
0.03*6000+0.05*4000=380
180+200=380
380=380
If this statement is TRUE and neither x nor y is negative then all is well
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