Question 1064669
Let {{{ a }}} = number of children attended
Let {{{ b }}} = number of adults attended
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(1) {{{ a + b = 1486 }}}
(2) {{{ 1.5a + 4b = 3479 }}}
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Multiply both sides of (2) by {{{ 2 }}}
(2) {{{ 3a + 8b = 6958 }}}
Multiply both sides of (1) by {{{ 3 }}}
and subtract (1) from (2)
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(2) {{{ 3a + 8b = 6958 }}}
(1) {{{ -3a - 3b = -4458 }}}
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{{{ 5b = 2500 }}}
{{{ b = 500 }}}
and
(1) {{{ a + b = 1486 }}}
(1) {{{ a + 500 = 1486 }}}
(1) {{{ a = 986 }}}
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500 adults attended
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check:
(2) {{{ 1.5a + 4b = 3479 }}}
(2) {{{ 1.5*986 + 4*500 = 3479 }}}
(2) {{{ 1479 + 2000 = 3479 }}}
(2) {{{ 3479 = 3479 }}}
OK