Question 553488
Let {{{ a }}} = amount invested @ 5%
Let {{{ b }}} = amount invested @ 10%
given:
(1) {{{ a + b = 8000 }}}
(2) {{{ .05a + .1b = 650 }}}
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(2) {{{ 5a + 10b = 65000 }}}
Multiply both sides of (1) by {{{ 5 }}}
and subtract (1) from (2)
(2) {{{ 5a + 10b = 65000 }}}
(1) {{{ -5a - 5b = 40000 }}}
{{{ 5b = 25000 }}}
{{{ b = 5000 }}}
and, since
(1) {{{ a + b = 8000 }}}
(1) {{{ a + 5000 = 8000 }}}
(1) {{{ a = 3000 }}}
He invested $3,000 @ 5% and
$5,000 @ 10%
check answer:
(2) {{{ .05a + .1b = 650 }}}
(2) {{{ .05*3000 + .1*5000 = 650 }}}
(2) {{{ 150 + 500 = 650 }}}
(2) {{{ 650 = 650 }}}
OK