Question 529293
Let {{{a}}} = amount invested @ 4%
Let {{{b}}} = amount invested @ 5%
given:
(1) {{{ a + b = 100000 }}}
(2) {{{ .04a + .05b = 4850 }}}
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(2) {{{ 4a + 5b = 485000 }}}
Multiply both sides of (1) by {{{4}}}
and subtract (1) from (2)
(2) {{{ 4a + 5b = 485000 }}}
(1) {{{ -4a - 4b = -400000 }}}
{{{ b = 85000 }}}
and, since
(1) {{{ a + b = 100000 }}}
(1) {{{ a + 85000 = 100000 }}}
(1) {{{ a = 15000 }}}
Cliff invested $15,000 in bank A
check answer:
(2) {{{ .04a + .05b = 4850 }}}
(2) {{{ .04*15000 + .05*85000 = 4850 }}}
(2) {{{ 600 + 4250 =4850 }}}
(2) {{{ 4850 = 4850 }}}
OK