If the cost price of 25 pens is equal to the selling price of 20 pens, then profit percent is = ?

Answer: Option B

CP of 25 pens = SP 20 pens
$$\frac{\text{CP}}{\text{SP}}=\frac{20}{25}=\frac{4}{5})1=\text{Profit}$$
$$\begin{array}{rl}& \text{Profit }\%=\frac{1}{4}\times 100\\ & =25\%\end{array}$$