Question 1095541
Let {{{ x }}} = the number that Alex designs
{{{ 3x }}} = the number that Mindy designs
{{{ 3x + 9 }}} = the number that Cara designs
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{{{ x + 3x + 3x + 9 = 58 }}}
{{{ 7x + 9 = 58 }}}
{{{ 7x = 49 }}}
{{{ x = 7 }}}
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Alex designs 7 ads
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check:
{{{ 7 + 21 + 21 + 9 = 58 }}}
{{{ 58 = 58 }}}
OK