Raspberry juice

How much will the scout leader pay for drinks for the children if a third of the children had a raspberry juice for 10 CZK, half of the children had sparkling water for 15 CZK, and the remaining 4 children had a kola for 20 CZK (CZK = Czech crowns)?

Correct answer:

x =  340 Kc

Step-by-step explanation:

$$\begin{gathered} \frac{n}{3}+\frac{n}{2}+4=n \\ n/3+n/2+4=n \\ n=24 \\ n=\frac{24}{1}=24 \\ n=24 \\ x=10\cdot \frac{n}{3}+15\cdot \frac{n}{2}+4\cdot 20=10\cdot \frac{24}{3}+15\cdot \frac{24}{2}+4\cdot 20=340\text{Kc} \end{gathered}$$

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