Question 95959
Arlene wishes to invest $5000. If she invest part at 7% simple enterest, part at 6%, and receives a total of $332 after one year, how much does she invest at each rate? 
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A quick comment on per cent.  I'm sure you know 50% is half of something and
100% is all of something, the word "cent" means one hundred, (think of century)
50% can be written {{{ 50/100}}} or .50, is the decimal equivalent.
 In our problem 7% is .07, right.
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In this problem. Each step is easy to understand, as I will show you.
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Choose one value for x:
x = amt invested 7%
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The problem gives the total as $5000, therefore we can say:
(5000-x) = amt invested at 6%, right?
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All we have to do now, is write the sum of the interests:
.07x  +  .06(5000-x)  = 332
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Multiply what is inside the brackets:
.07x + 300 - .06x = 332
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Perform some basic algebra, subtract 300 from both sides:
.07x - .06x = 332 - 300
.01x = 32
x = 32/.01; divided both sides by .01
x = $3200 is the amt invested at 7%
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Remember: (5000 - x) = amt invested at 6%, therefore
5000 - 3200 = $1800, amt invested at 6%
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A quick check of out solutions on calc enter:
.07(3200) + .06(1800) = 332
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I encourage you to read this over until you can say,"I got!", you will be able
to do all these type of problems with ease. Perhaps even show someone else how. 
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Hopefully I can say, "A student that I was in contact with today, actually
learned something from me." How about it?