Problem Solving

Hello vjesus12.

Let's take a look at your question.

Derek can read x pages in 5 minutes, this implies that Derek can read $$\frac{x}{5}\ \text{pages}\ \text{per}\ \text{minute}.$$ Therefore, to read p pages will take him $$\frac{p}{\frac{x}{5}}=\frac{5p}{x}\ \text{minutes}.$$ Hence, the correct answer is the option A.

I hope this explanation may help you.

I'm available if you'd like a follow-up.

Regards.