SOLUTION: a portion of $7000 is invested in a CD earning 4% and the remainder is in a savings bond earns 7%. if total interest earned after one year is $420, how much money was invested at e
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-> SOLUTION: a portion of $7000 is invested in a CD earning 4% and the remainder is in a savings bond earns 7%. if total interest earned after one year is $420, how much money was invested at e
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Question 315672: a portion of $7000 is invested in a CD earning 4% and the remainder is in a savings bond earns 7%. if total interest earned after one year is $420, how much money was invested at each rate? What is the formula for this problem? Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website! There's no formula, you need to set up a linear system of equations.
Let A be the amount at 4%, B the amount at 7%.
The total amount invested,
1.
The interest received,
2.
Multiply eq. 1 by (-4) and add to eq. 2 to eliminate A and solve for B,
Then from eq. 1,
