You are given
a commission of $10 for $100 in sales. You are to find the commission for $150
in sales. It is stated in the problem that the salesman’s commission varies
directly as his sales. Directly means proportional, and so this relationship has
a constant. Let us say the salesman commission is c and his sales is s. Let us
also denote k as our constant.
C = ks
$10 = k($100)
k = 0.1
We need to find
the salesman commission in $150 sales.