Question

Jane invested $13,000, a portion earning a simple interest rate of 3 and 1/4th% per year and the rest earning a rate of 3% per year. After one year the total interest earned on these investments was $411.25. How much money did she invest at EACH rate? FIFTEEN PTS!!!

Answer 1

The interest rate of the first portion is
R=3+(1÷4)=3.25%

Now set the equation
0.03x+0.0325 (13000-x)=411.25
Solve for x to find the amount invested at 3%
0.03x+422.5-0.0325x=411.25
0.03x-0.0325x=411.25-422.5
−0.0025x=-11.25
X=11.25÷0.0025
X=4,500 invested at 3%

13,000−4,500=8,500 invested at 3.25%

Hope it helps!