Question 1148298: Jerry invested $10,000, part at 8% simple interest and the rest at 5% simple interest for a period of 1 year. If he received a total annual interest of $575 from both investments, how much did he invest at each rate?
Answer by greenestamps(13200)   (Show Source):
You can put this solution on YOUR website!
Using the traditional algebraic solution method....
8% of x, plus 5% of ($10,000-x), equals $575:
ANSWER: $2500 at 8%; the other $7500 at 5%.
Here is a non-algebraic method that will get you to the solution to "mixture" problems like this much faster and with far less work, if you understand how to use it.
(1) The $10,000 all earning 8% interest would yield $800 interest; all at 5% would yield $500 interest.
(2) The actual interest, $575, is 1/4 of the way from $500 to $800. (Picture the three numbers on a number line -- 500, 575, and 800; 575 is 1/4 of the way from 500 to 800.)
(3) That means 1/4 of the total was invested at the higher rate.
ANSWER: 1/4 of $10,000, or $2500, at 8%; the other $7500 at 5%.
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