Question

Phyllis invested $11,000, a portion earning a simple interest rate of

2
1
2
%
per year and the rest earning a rate of 2% per year. After one year the total interest earned on these investments was $255.00. How much money did she invest at each rate?

Answer 1

First = 1000

Second = 10,000

Explanation:

Given the following :

Amount invested = $11,000

A portion earns 2 1/2 % interest per year

The rest earns a rate of 2% per year

Total Interst earned after a year = $255

Amount invested at each rate

Let amount invested at 2 1/2% = a

Amount invested at 2% = 11,000 - a

Simple interest = principal * rate * time

First investment :

a * 5/2% * 1

Second :

(11000 - a) * 2%

Firat investment + second = $225

a * 0.025 + (11000 - a) * 0.02 = 225

0.025a + 220 - 0.02a = 225

0.005a = 225 - 220

0.005a = 5

a = 5 / 0.005

a = 1000

Amount in first investment = 1000

Second investment = 11000 - 1000 = 10,000