SOLUTION: Annie-Sophie invested some of her $20,000 in bonds that made an 8% profit and the rest in bonds that made a 7% profit. If the profit on the 8% bonds was $700 more than the profit o

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Question 188298This question is from textbook Teaching Textbook
: Annie-Sophie invested some of her $20,000 in bonds that made an 8% profit and the rest in bonds that made a 7% profit. If the profit on the 8% bonds was $700 more than the profit on the 7% bonds, how much did Anne-Sophie invest in the 7% bonds? This question is from textbook Teaching Textbook

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Let x = money invested money that made 8% profit

Then, $20,000 - x = money invested at 7% profit

Also, let y = profit for 7% bonds

Then again, $700 + y = profit for 8%, $700 more than profit on 7%.

Putting into eqn for 8%:
0.08%28x%29=700%2By --------------------> Eqn 1

Putting into eqn for 7%:
%2820000-x%29%280.07%29=y ----------------> Eqn 2

In Eqn 1 we get, y=0.08%28x%29-700 -----> Eqn 3, substitute in Eqn 2:

%282000-x%29%280.07%29=highlight%28%280.08%29%28x%29-700%29
1400-0.07x=0.08x-700
1400%2B700=0.08x%2B0.07x
2100=0.15x------> cross%282100%2914000%2Fcross%280.15%29=cross%280.15%29x%2Fcross%280.15%29

x = $14,000 money invested for 8%

$20,000 - $14,000 = $6,000 money invested for 7%.( Answer)

Let's check the Profit

For 7%
$6000 x 0.07 = $420

For 8%
$14,000 x 0.08 = $1120

Profit (8%) - Profit (7%) = $1120 - $420 = $700
That is right, $700 more on 8%.

Thank you,
Jojo