Problema Solution
Phyllis invested $12,000, a portion earning a simple interest rate of 4 1/2% per year and the rest earning a rate of 4% a year. After 1 year the total interest earned on the investment was $525. How much money did she invest at each rate?
Answer provided by our tutors
let 'x' represent the amount invested at 4.5%, then '12000-x' represents the amount invested at 4%
interest = principal * rate * time
we assume time to be equal to 1
525 = 0.045x + 0.04(12000-x)
solving for 'x' we have x=9000
12000-9000 = 3000
Phyllis invested $9,000 at 4.5% and $3,000 at 4%