Susan invests twice as much money at 7.5% as she does at 6%. If her total interest after a year is $840, how much does she have invested at each rate?

Let x be the amount invested at 6%
840 = 0.06x + 0.075(2x) 840 = 0.06x + 0.15x 840 = 0.21x x = 840/0.21 x = 4000
Therefore, she invests $4000 at 6% and $8000 at 7.5%

Answered by chipperrider | 2024-06-10

Susan invests $4000 at 6% and $8000 at 7.5%. After calculating based on her total interest of $840, we derived these amounts using simple algebra. The investments reflect her strategy of putting more into the higher interest rate account.
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Answered by chipperrider | 2024-10-10