SOLUTION: Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much
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-> SOLUTION: Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much
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Question 1095066: Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much did he invest at each rate? Found 2 solutions by josmiceli, MathTherapy:Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
(1)
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(2)
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(3)
(4)
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Substitute (1) and (2) into (3)
(3)
(3)
(3)
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Multiply both sides of (4) by
and subtract (4) from (3)
(3)
(4)
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and
(4)
(4)
(4)
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He invested $2,650 @ 8%
He invested $400 @ 7.5%
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check:
(1)
(1)
(1)
and
(2)
(2)
and
(3)
(3)
OK
You can put this solution on YOUR website!
Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much did he invest at each rate?
Let the 8%-investment amount be E
Then the 7.5% investment amount = 3,050 - E
We then get: .08E + .075(3,050 - E) = 242
.08E + 228.75 - .075E = 242
.08E - .075E = 242 - 228.75
.005E = 13.25
E, or 8%-investment amount =
Amount invested at 7.5%:
That's all!! Nothing COMPLEX and/or CONFUSING!
P.S. I could've also used 2 variables: 1 for the 8% and another for the 7.5%.
