SOLUTION: Michael invested a total of $14,000 in two certificates of deposit. One pays 5% interest, and the other pays 6% interest. His total interest at the end of one year is $780. How muc

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Michael invested a total of $14,000 in two certificates of deposit. One pays 5% interest, and the other pays 6% interest. His total interest at the end of one year is $780. How muc      Log On

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Question 318823: Michael invested a total of $14,000 in two certificates of deposit. One pays 5% interest, and the other pays 6% interest. His total interest at the end of one year is $780. How much is invested in the CD that pays 5% interest?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the amount in 5% and B the amount in 6%.
1.A%2BB=14000
.
.
.
0.05A%2B0.06B=780
2.5A%2B6B=78000
Multiply eq. 1 by -5 and add it to eq. 2 to eliminate A.
-5A-5B%2B5A%2B6B=-70000%2B78000
highlight%28B=8000%29
Then from eq. 1,
A%2B8000=14000
highlight%28A=6000%29