# Arlene wishes to invest \$5000. If she invests part at 7% simple interest, and part at 6%, and receives at total of \$332 after one year, how much does sh invest at each rate?

1
by maryandrearoseg

2015-03-02T14:48:34+08:00

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Let 'x' be the amount invested at 7%
'y' be the amount invested at 6%
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Since the total amount is 5,000 then you'll have it as:
x + y = 5,000    ----equation 1
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Since the amount invested will have an interest of 332 at the end of one year then:
0.07x + 0.06y = 332
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From equation 1:
x + y = 5,000
x = 5,000 - y      ----equation 1'
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Substitute equation 1' to equation 2
0.07x + 0.06y = 332
0.07(5,000-y) + 0.06y = 332
350 - 0.07y + 0.06y = 332
- 0.07y + 0.06y = 332 - 350
-0.01y = 18
y = 1,800
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Substitute y=1,800 to equation 1'
x = 5,000 - 1,800
x = 3,200
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Therefore 1,800 was invested at 6% and 3,200 was invested at 7%