Question 1164248: You invested $5000 between two accounts paying 3% and 7% annual interest, respectively. If the total interest earned for the year was $190 how much was invested at each rate of 3% and 7%?
Answer by greenestamps(13200)   (Show Source):
You can put this solution on YOUR website!
(1) A typical formal algebraic setup for solving the problem:
x amount at 3%, plus ($5000-x) amount at 7%, yields $190 interest.
Solve using basic algebra; I leave that to you.
(2) A quick and easy way to solve any two-part "mixture" problem like this, if a formal algebraic solution is not required:
$5000 all invested at 3% would yield $150 interest; all at 7$ would yield $350 interest.
The actual interest, $190, is 40/200 = 1/5 of the way from $150 to $350. (If it helps, picture the three dollar amounts 150, 190, and 350 on a number line; 150 to 190 is a difference of 40, 150 to 350 is a difference of 200, so 190 is 40/200 = 1/5 of the distance from 150 to 350.)
That means 1/5 of the total was invested at the higher rate.
ANSWER: 1/5 of the $5000, or $1000, at 7%; the other $4000 at 3%.
CHECK: .03(4000)+.07(1000) = 120+70 = 190
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