Question 69242
Jane invested some amount at the rate of 12% simple interest and some other amount at the rate of 10% simple interest.  She received yearly interest of $130.  Randy also invested in the same scheme, but he interchanged the amounts invested, and received $4 more as interest.  How much amount did each of them invest a different rates?

So far, I have:
1st: x(.12) + y(.10)= $130
2nd: x(0.10) + y(0.12) = $134

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Multiply each equation by 100 to get:
3rd: 12x + 10y = 13000
4th: 10x + 12y = 13400
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Multiply 3rd by 10 and 4th by 12 to get:
5th: 120x + 100y = 130000
6th: 120x + 144y = 160800
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Subtract 5th from 6th to get:
44y = 30800
y=$700
Substitute into 4th to find "x"
10x+12*700 = 13400
10x + 8400 = 13400
10x = 5000
x=$500 
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Amounts invested were $700 and $500
Cheers,
Stan H.