SOLUTION: jordan had $15,000 to invest. he invested some at 5% and the rest at 6%. at the end of the year he had made $860. how much did he invest at each amount?

Question 490171: jordan had $15,000 to invest. he invested some at 5% and the rest at 6%. at the end of the year he had made $860. how much did he invest at each amount?
Found 2 solutions by mananth, ej_03:
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Investment I 5.00% per annum ---x
Investment II 6.00% per annum ---y

x + y= 15000 ------------------------1
5.00% x + 6.00% y = $860.00
Multiply by 100
5 x + 6 y = $86,000.00 --------2

Multiply (1) by -5
we get

-5 x -5 y = -75000.00

Add this to (2)

0 x 1 y = $11,000.00

divide by 1

y = $11,000.00 investment at
Balance $4,000.00 investment at
CHECK
$4,000.00 $200.00
$11,000.00 $660.00
Total $860.00

Answer by ej_03(8) (Show Source): You can put this solution on YOUR website!
let a=5%
b=6%
eq1 a+b=15000
b=15000-a
eq2 .05a+.06(15000-a)=860
perform the indicated operations in the equation:
.05a+.06(15000-a)=860
.05a+900-.06a=860
.05a-.06a=860-900
.01a/.01a=40/.01
a=4000
b=15000-4000=11000
therefore he invested 11000 at 6% and 4000 at 5%...

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