Question 955889
{{{ I = P*r*t }}}
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Let {{{ p  }}} = amount invested @ 4%
{{{ p + 3000 }}} = amount invested @ 5%
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(1) {{{ I[1] = p*.04*1 }}}
(2) {{{ I[2] = ( p + 3000 )*.05*1 }}}
(3) {{{ I[1] + I[2] = 510 }}}
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{{{ 510 = .04p + ( p + 3000 )*.05 }}}
{{{ 510 = .04p + .05p + 150 }}}
{{{ .09p = 360 }}}
{{{ p = 4000 }}}
and
{{{ p + 3000 = 7000 }}}
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$4,000 is invested @ 4%
$7,000 is invested @ 5%
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check:
(1) {{{ I[1] = .04p }}}
(1) {{{ I[1] = .04*4000 }}}
(1) {{{ I[1] = 160 }}}
and
(2) {{{ I[2] = .05*( p + 3000 ) }}}
(2) {{{ I[2] = .05*7000 }}}
(2) {{{ I[2] = 350 }}}
and
(3) {{{ I[1] + I[2] = 510 }}}
(3) {{{ 160 + 350 = 510 }}}
(3) {{{ 510 = 510 }}}
OK