Math Problem Statement

A person invests a total of $5,000 in two accounts. One account earns 5% interest, and the other earns 8% interest. At the end of the year, the total interest from both accounts is $340. How much was invested in each account? $2,000 invested at 5%, and $3,000 at 8%

Solution

To solve this problem, we set up a system of equations based on the information provided:

Let:

  • xx = amount invested at 5%
  • yy = amount invested at 8%

We know:

  1. The total investment is $5,000: x+y=5000x + y = 5000
  2. The total interest earned from both accounts is $340: 0.05x+0.08y=3400.05x + 0.08y = 340

Solving the System of Equations

Step 1: Solve for yy in terms of xx using the first equation

From x+y=5000x + y = 5000: y=5000xy = 5000 - x

Step 2: Substitute y=5000xy = 5000 - x into the second equation

Substitute into 0.05x+0.08y=3400.05x + 0.08y = 340: 0.05x+0.08(5000x)=3400.05x + 0.08(5000 - x) = 340

Expanding and simplifying: 0.05x+4000.08x=3400.05x + 400 - 0.08x = 340 0.03x=60-0.03x = -60 x=600.03=2000x = \frac{-60}{-0.03} = 2000

Step 3: Substitute x=2000x = 2000 back into y=5000xy = 5000 - x

y=50002000=3000y = 5000 - 2000 = 3000

Solution

  • x=2000x = 2000: $2,000 was invested at 5%
  • y=3000y = 3000: $3,000 was invested at 8%

This matches the solution you provided.

Would you like a detailed breakdown of the steps?


Related questions:

  1. What would the investments be if the total interest was different?
  2. How does changing the interest rates affect the amounts invested?
  3. What happens if the total investment is altered but interest rates remain the same?
  4. Can we solve similar problems with different percentages?
  5. How would the approach change if one interest rate was compounded?

Tip: Setting up equations based on given information is essential for solving investment problems effectively.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
System of Equations

Formulas

x + y = Total Investment
Interest Equation: Interest1 + Interest2 = Total Interest

Theorems

Substitution method for solving systems of linear equations

Suitable Grade Level

Grades 8-10