Question 1016563
Let {{{ P }}} = his profit
Let {{{ n }}} = number of hot dogs 
per month he sells
{{{ P = 3n - 2000 - .5n }}}
When he breaks even, {{{ P = 0 }}} 
{{{ 0 = 3n - 2000 - .5n }}}
{{{ 2.5n = 2000  }}}
{{{ n = 800 }}}
If he sells 800 hot dogs, he breaks even
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If he sells 1000 hot dogs
{{{ P = 3n - 2000 - .5n }}}
{{{ P = 2.5*1000 - 2000  }}}
{{{ P = 2500 - 2000 }}}
{{{ P = 500 }}}
His profit would be $500