Question 1137195
Let {{{ x }}} = number of pieces sold at original price
{{{ 89 - x }}} = number sold at reduced price
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{{{ 13.5x + 12.5*( 89 - x ) = 1133.5 }}}
{{{ 13.5x + 1112.5 - 12.5x = 1133.5 }}}
{{{ x = 1133.5 - 1112.5 }}}
{{{ x = 21 }}}
and
{{{ 89 - x = 68 }}}
21 sold at original price
68 sold at reduced price
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{{{ 13.5x + 12.5*( 89 - x ) = 1133.5 }}}
{{{ 13.5*21 + 12.5*68 = 1133.5 }}}
{{{ 283.5 + 850 = 1133.5 }}}
{{{ 1133.5 = 1133.5 }}}
OK