Question 763585
Let {{{ S }}} = her monthly salary + any commission
Let {{{ a }}} = her amount of sales in plan B
With plan A:
{{{ S = 2*2750 }}}
{{{ S = 5500 }}} 
With Plan B:
{{{ S = 2*2100 + .0725a }}}
{{{ S = 2*2100 + .0725a }}}
{{{ S = 4200 + .0725*9000 }}}
{{{ S = 4200 + 652.5 }}}
{{{ S = 4852.5 }}}
{{{ 5500 - 4852.5 = 647.5 }}}
She can expect to make $647.50 more per month with plan A