Question 432700
First I want to know when the plans are the same
Let {{{s}}} = Monthly Sales
Plan A:
Monthly Salary, A = {{{900 + .1s }}} 
Plan B:
Monthly Salary, B = {{{ 1200 + .15s }}}
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Unless you copied the problem wrong, it looks
like plan B is always better than plan A.
The monthly salary is better, and the
commission is better.