# Phyllis invested $11,500, a portion earning a simple interest rate of 1 1/4% per year and the rest earning a rate of 1% per year. After....?

Phyllis invested $11,500, a portion earning a simple interest rate of

1 1/4% per year and the rest earning a rate of 1% per year. After one year the total interest earned on these investments was $136.25. How much money did she invest at each rate?

### 1 Answer

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- AlvinLv 41 month agoFavourite answer
let x = amount invested at 1 1/4 %

11500-x = amount invested at 1 %

1.0125x + (11500-x)1.01 = 11500+ 136.25

0.0025x + 11500*1.01 = 11636.25

0.0025x + 11615 = 11636.25

0.0025x = 11636.25 -11615 = 21.25

x = 21.25/ .0025 = 8500

x =8500

11500 -8500 = 3000

8500 at 1 1/4 %

and

3000 at 1%

8500*1.0125 + 3000*1.01 = 11636.25

(it checks)

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