## Elementary Algebra

We can use the following guideline to solve this problem: Rate of profit = $\frac{Selling\ price -\ Cost}{Cost}$ $\times$ 100% Selling price = 56 Cost = 42 Substituting these values into the formula gives: Rate of profit = $\frac{56-42}{42}$ $\times$ 100% Rate of profit = $\frac{14}{42}$ $\times$ 100% Rate of profit = 0.333333 $\times$ 100% Rate of profit $\approx$ 33.3%