Mr. Strauss invests $4000, part at 6%, and part at 7%. His income from these investments in one year is $250. Find the amount invested at 7%
2007-07-25 10:57:52 · 3 answers · asked by wu_4533 2 in Science & Mathematics ➔ Mathematics
let's say x is at 6%. The remainder of the $4000 is at 7%:
(x * 0.06) + (4000 - x) * 0.07 = 250
0.06x + 4000*0.07 - 0.07x = 250
280 - 0.01x = 250
30 = 0.01x
x = 3000
3000 @ 6%
1000 @ 7%
Checking the answer:
3000 @ 6% = 3000 * 0.06 = $180
1000 @ 7% = 1000 * 0.07 = $70
$180 + $70 = $250
2007-07-25 11:00:23 · answer #1 · answered by McFate 7 · 1⤊ 0⤋
Let x = amount invested at 6%
(4000 - x) = amount invested at 7%
interest = [principle*years*rate]/100
250 = (x)(6)/100 + (4000 - x)(7)/100
25000 = 6x + 28000 - 7x
x = 3000
He invests $ 3000 at 6% and $ 1000 at 7%.
2007-07-25 18:02:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
.07x + .06(4000 - x) = 250
.07x + 240 - .06x = 250
.01x = 10
x = 1000
Check
.07(1000) + .06(3000) = 250
70 + 180 = 250
250 = 250
2007-07-25 18:05:58 · answer #3 · answered by kindricko 7 · 0⤊ 0⤋