Question

Chris can be paid in one of two ways. Plan A is a salary of $350 per month, plus a commission of 7% of a sales. pLan B is a salary of $436 per month, plus a commission of 5% of sales. For what amount of sales is Chris better off selecting plan A

Answer 1

let's say, the total sales is "x"... .so hmm on Plan A, he gets 350 plus 7% of "x", well, 7% is just (7/100) * x or 0.07x

now, on Plan B, he gets 436 plus 5% of "x", 5% of "x" is (5/100) * x, or 0.05x

he's better off with A, only if A is greater than B, namely, A > B

$\bf A\ \textgreater \ B\implies 350+0.07x\ \textgreater \ 436+0.05x \\\\\\ 0.07x-0.05x\ \textgreater \ 436-350\implies 0.02x\ \textgreater \ 86\implies x\ \textgreater \ \cfrac{86}{0.02}$

and surely you know how much that is.