Flower watering options

Alena, Ivana, Edo, Philip, and Martin came late to school. As a punishment, two will water flowers all over the school after class, and the other three will clean up the classroom. The class teacher couldn't decide who to send to water the flowers, so George started listing all the options for her. Complete his solution.

Final Answer:

n =  10

Step-by-step explanation:

$$\begin{gathered} C_2(5)=\left(\genfrac{}{}{0ex}{}{5}{2}\right)=\frac{5!}{2!(5-2)!}=\frac{5\cdot 4}{2\cdot 1}=10 \\ n=\left(\genfrac{}{}{0ex}{}{2}{5}\right)=10 \end{gathered}$$

Try another example