SOLUTION: Bob invested $24000. He invested part of it at 8% interest per year and the rest at 10% interest per year. His total interest income for the year is $2300. How much was invested a

Algebra ->  Human-and-algebraic-language -> SOLUTION: Bob invested $24000. He invested part of it at 8% interest per year and the rest at 10% interest per year. His total interest income for the year is $2300. How much was invested a      Log On


   



Question 1145315: Bob invested $24000. He invested part of it at 8% interest per year and the rest at 10% interest per year. His total interest income for the year is $2300. How much was invested at 10%?
Thanks

Found 2 solutions by richwmiller, greenestamps:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=24000
a=24000-b
.08*a+.10*b=2300
solve for b
.08*(24000-b)+.10*b=2300

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


For an alternative to the traditional algebraic process for solving "mixture" problems like this, try this...:

(1) $24000 all invested at 8% would return $1920 interest; all at 10% would return $2400 interest.
(2) The actual interest amount, $2300, is 380/480 = 38/48 = 19/24 of the way from $1920 to $2400.
(3) Therefore 19/24 of the money was invested at the higher rate.

ANSWER: 19/24 of $24000, or $19000 at 10%; the rest at 8%.

CHECK: .10(19000)+.08(5000) = 1900+400 = 2300