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Let x be the amount invested at 14% (in dollars, of course).
Then the amount invested at 4% is 3x ("three times as much . . . ").
The total interest is the sum of partial interests
0.04*(3x) + 0.14x = 260 dollars.
Simplify and solve
0.12x + 0.14x = 260
0.26x = 260
x = = 1000.
ANSWER. $1000 invested at 14% and 3 * $1000 = $3000 invested at 4%.
CHECK. 0.14*1000 + 0.04*3000 = 260 dollars. ! Precisely correct !
Solved.
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It is a standard and typical problem on investments.
If you need more details, or if you want to see other similar problems solved by different methods, look into the lesson
- Using systems of equations to solve problems on investment
in this site.
You will find there different approaches (using one equation or a system of two equations in two unknowns), as well as
different methods of solution to the equations (Substitution, Elimination).
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic "Systems of two linear equations in two unknowns".
Save the link to this online textbook together with its description
Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson
to your archive and use it when it is needed.
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