.
Let x = the amount invested in fund A at 6% and
let y = the amount invested in fund B at 7%.
Then your first equation is
y - x = 5000. (1)
Fund A returned 0.06*x dollars; fund B returned 0.07*y dollars.
So, you second equation is
interest + interest = total interest, or
0.06x + 0.07y = 2300 dollars (2)
From equation (1) express y = 5000+x and substitute it into equation (2), replacing y:
0.06x + 0.07*(5000+x) = 2300.
Sinplify and solve for x:
0.06x + 350 + 0.07x = 2300
0.13x = 2300 - 350 = 1950 ====> x = = 15000.
Answer. The amount invested in fund A is $15000; the amount invested in fund B is 5000 more, i.e. $20000.
Check. 0.06*15000 + 0.07*20000 = 2300 dollars. ! Correct !
Solved.
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To see many other similar solved problems on investment, 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".
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Free of charge online textbook in ALGEBRA-I
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to your archive and use it when it is needed.