Question 316559
Let x = amount invested at 4%
Let y = amount invested at 6.5%


You have two variables, so you need two equations:


Equation 1: x+y = 5000   (the sum of money invested was $5000)
Equation 2: 0.04x + 0.065y = 282.50      (the sum of the interest earned)



Isolate for one of the variables in Equation 1, then plug it into Equation 2. I will choose to isolate for x:


x = 5000-y

0.04(5000-y) + 0.065y =282.50
200-0.04y +0.065y = 282.50
0.025y = 82.50
y=3300


x =5000-y
x=1700


So $1700 was invested at 4% and $3300 was invested at 6.5%.