Question

4 students is what percentage of 20 students?2 doctors is _____% of 25 doctors.

Answer 1

In both cases, we can use a rule of three.

First part

$\begin{gathered} 20\text{ students}\rightarrow100\text{\%} \\ 4\text{ students}\rightarrow x \\ x=\frac{4\text{ students}\cdot100\text{\%}}{20\text{ students}} \\ x=\frac{4\cdot100\text{\%}}{20} \\ x=\frac{400\text{\%}}{20} \\ x=20\text{\%} \end{gathered}$

Therefore, 4 students correspond to 20% of 20 students in total.

Second part

$\begin{gathered} 25\text{ doctors}\rightarrow100\text{\%} \\ 2\text{ doctors}\rightarrow x \\ x=\frac{2\text{ doctors}\cdot100\text{\%}}{25\text{ doctors}} \\ x=\frac{2\cdot100\text{\%}}{25} \\ x=\frac{200\text{\%}}{25} \\ x=8\text{\%} \end{gathered}$

Therefore, 2 doctors correspond to 8% of 25 doctors in total.