Question 1153715
Let {{{ a }}} = number of drinks she buys
Let {{{ b }}} = number of pretzels she buys
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{{{ 5.5a + 4b <= 90 }}}
{{{ a + b >= 18 }}}
{{{ a = 5 }}}
{{{ 5 + b >= 18 }}}
{{{ b >= 13 }}}
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{{{ 5.5*5 + 4b <= 90 }}}
{{{ 27.5 + 4b <= 90 }}}
{{{ 4b <= 62.5 }}}
{{{ b <= 15.625 }}}
you can't have part of a pretzel, so
the maximum number of pretzels
is 15
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get a 2nd opinion if needed