math problem?

0 ⤊

Barbara invests $2,400 in the national bank at 5%.
How much additional money must she invest at 8%
so that the total annual income will be equal to 6% of her entire investment?

$1200
$3000
$1000
$3600
$2400

2007-01-28 09:00:22 · 2 answers · asked by devincr 1 in Science & Mathematics ➔ Mathematics

2 answers

set up variables...x for additional money needed:

set up equations: (x + 2400) * 6% = 2400 * 5% + x * 8%

find x.

2007-01-28 09:08:19 · answer #1 · answered by jsd 2 · 0⤊ 0⤋

2400*.05 +.08 x = (2400+x).06
120 +.08x = 144 +.06x
.02x = 24
x=24/.02= $1200

2007-01-28 09:13:15 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋