investment question

Question

?$6300
is? invested, part of it at 12?%
and part of it at 7?%.
For a certain? year, the total yield is 596.00.
How much was invested at each? rate?


How much was invested at
12%

Answer 1

 

I am assuming simple interest ... I = Prt ... P is principal, r is rate, t is time in years (1 year for this problem)

 

Let x = amount invested at 12%

Let y = amount invested at 7%

 

 

Equation (1) ...        x + y = 6300

Equation (2) ...   .12x + .07y = 596

   

Solve the system using substitution method

 

    Solving for y in equation 1, y = 6300 - x

 

    Now we have

    .12x + .07(6300 -x) = 596

    .12x + 441 -.07x = 596

    .05x = 155

    x = 3100

 

    $3100 is invested at 12%

    

    Subtract that from 6300 to obtain the amount invested at 7% ... 6300 - 3100 = 3200

 

    $3200 is invested at 7%