Question 1150492
Let {{{ P }}} = amount invested @ 6%
{{{ 10000 - P }}} = amount invested @ 9%
Let {{{ I }}} = gain from 6% investment
{{{ 684 - I }}} = gain from 9% investment
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{{{ I = P*r*t }}}
(1) {{{ I = P*.06*1 }}}
(2) {{{ 684 - I = ( 10000 - P )*.09*1 }}}
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(2) {{{ 684 - I = 900 - .09P }}}
(2) {{{ .09P - I = 216 }}}
Plug (1) into (2)
(2) {{{ .09P - .06P = 216 }}}
(2) {{{ .03P = 216 }}}
(2) {{{ P = 7200 }}}
and
{{{ 10000 - P = 2800 }}}
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$7,200 invested @ 6%
$2,800 invested @ 9%
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check:
(1) {{{ I = P*.06*1 }}}
(1) {{{ I = 7200*.06 }}}
(1) {{{ I = 432 }}}
and
(2) {{{ 684 - I = ( 10000 - P )*.09*1 }}}
(2) {{{ 684 - I = 2800*.09 }}}
(2) {{{ I = 684 - 252 }}}
(2) {{{ I = 432 }}}
Ok