SOLUTION: You invested $ 4000 between two accounts paying 2 % and 7 % annual interest, respectively. If the total interest earned for the year was $ 230, how much was invested at each
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Question 1156044: You invested $ 4000 between two accounts paying 2 % and 7 % annual interest, respectively. If the total interest earned for the year was $ 230, how much was invested at each rate? Answer by greenestamps(13200) (Show Source):
Solve using basic algebra (straightforward, but it takes time)....
Here is how I prefer to solve two-part "mixture" problems like this. It uses only logical reasoning and a few simple mental calculations -- as opposed to writing and solving an algebraic equation.
$4000 all at 2% would yield $80 interest
$4000 all at 7% would yield $280 interest
The actual interest of $230 is 3/4 of the way from $80 to $280 (80 to 280 is 200; 80 to 230 is 150; 150/200 = 3/4)
Therefore 3/4 of the $4000 was invested at the higher rate.
ANSWER: 3/4 of the $4000, or $3000, was invested at 7%; the remaining $1000 was invested at 2%.
