# Math

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melissa invested a some of money at 3% annual simple inter she invested 3 times that some at 5 % annual simple interest

if her total yearly interest from both investments was 7200 how much was invested at 3% ?

• Math -

Invested \$X @ 3%.
Invested \$3X @ 5%.

0.03X + 0.05*3X = 7200.
0.03X + 0.15X = 7200,
0.18X = 7200.
X = \$40,000.

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