document.write( "Question 547100: aling martha invested part of her P20,000 at 8% interest and the remaining at 7%. If the total earnings for the investment is P1520, how much did she invest at 8%? \n" ); document.write( "
Algebra.Com's Answer #356261 by mananth(16949)\"\" \"About 
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Fund A 8.00% per annum ---x
\n" ); document.write( "Fund B 7.00% per annum ---y
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\n" ); document.write( "x + y= 20000 ------------------------1
\n" ); document.write( "8.00% x + 7.00% y= = $1,520.00
\n" ); document.write( "Multiply by 100
\n" ); document.write( "8 x + 7 y= = $152,000.00 --------2
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\n" ); document.write( "Multiply (1) by -8
\n" ); document.write( "we get
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\n" ); document.write( "-8 x -8 y= = -160000.00
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\n" ); document.write( "Add this to (2)
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\n" ); document.write( "0 x -1 y= = -P8,000.00
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\n" ); document.write( "divide by -1
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\n" ); document.write( "y = P8,000.00 investment at 7.00%
\n" ); document.write( "Balance P12,000.00 investment at 8.00%
\n" ); document.write( "CHECK
\n" ); document.write( "$12,000.00 --------- 8.00% ------- P960.00
\n" ); document.write( "$8,000.00 ------- 7.00% ------- P560.00
\n" ); document.write( "Total -------------- P1,520.00
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