Question 659732
Let {{{ a }}} = amount invested in 3.2% bond
Let {{{ b }}} = amount invested in 3% bond
given:
(1) {{{ a + b = 5200 }}}
(2) {{{ .032a + .03b = 162.45 }}}
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(2) {{{ 32a + 30b = 162450 }}}
Multiply both sides of (1) by {{{ 30 }}}
and subtract (1) from (2)
(2) {{{ 32a + 30b = 162450 }}}
(1) {{{ -30a - 30b = -156000 }}}
{{{ 2a = 6450 }}}
{{{ a = 3225 }}}
and, since
(1) {{{ a + b = 5200 }}}
(1) {{{ 3225 + b = 5200 }}}
(1) {{{ b = 1975 }}}
She invested $1,975 in the 3% bond
check:
(2) {{{ .032a + .03b = 162.45 }}}
(2) {{{ .032*3225 + .03*1975 = 162.45 }}}
(2) {{{ 103.2 + 59.25 = 162.45 }}}
(2) {{{ 162.45 = 162.45 }}}
OK