Question 1092177
Use {{{ I = P*r*t }}}
{{{ I[1] = P[1]*.03*1 }}}
(1) {{{ I[1] = .03P[1] }}}
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and
{{{ I[2] = .04P[2] }}}
{{{ P[2] = 4000 - P[1] }}}
{{{ I[2] = .04*( 4000 - P[1] ) }}}
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{{{ I[2] = 136 - I[1] }}}
{{{ 136 - I[1] = .04*( 4000 - P[1] ) }}}
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{{{ 136 - I[1] = 160 - .04P[1] }}}
(2) {{{ I[1] = .04P[1] - 24 }}}
Plug (1) into (2)
(2) {{{ .03P[1] = .04P[1] - 24 }}}
(2) {{{ .01P[1] = 24 }}}
(2) {{{ P[1] = 2400 }}}
and
{{{ P[2] = 4000 - P[1] }}}
{{{ P[2] = 4000 - 2400 }}}
{{{ P[2] = 1600 }}}
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$2,400 is invested @ 3%
$1,600 is invested @ 4%
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check:
(1) {{{ I[1] = .03P[1] }}}
(1) {{{ I[1] = .03*2400 }}}
(1) {{{ I[1] = 72 }}}
and
(2) {{{ I[2] = .04*P[2] }}}
(2) {{{ I[2] = .04*1600 }}}
(2) {{{ I[2] = 64 }}}
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{{{ I[1] + I[2] = 72 + 64 }}}
{{{ I[1] + I[2] = 136 }}}
OK