Question 686675
Let {{{ a }}} = number of $5 tickets bought
Let {{{ b }}} = number of $8 tickets bought
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(1) {{{ a + b =213 }}}
(2) {{{ 5a + 8b = 1254 }}}
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Multiply both sides of (1) by {{{ 5 }}}
and subtract (1) from (2)
(2) {{{ 5a + 8b = 1254 }}}
(1) {{{ -5a - 5b = -1065 }}}
{{{ 3b = 189 }}}
{{{ b = 63 }}}
and, since
(1) {{{ a + b =213 }}}
(1) {{{ a + 63 =213 }}}
(1) {{{ a = 150 }}}
150 $5 tickets were bought
63 $8 tickets were bought