Volleyball Tournament Matches Count

In the volleyball tournament, three domestic teams and four foreign teams played, each against each other, in single matches (no rematches). How many games have been played?

Final Answer:

n =  21

Step-by-step explanation:

$$\begin{gathered} d=3+4=7 \\ n=\frac{d\cdot (d-1)}{2}=\frac{7\cdot (7-1)}{2}=21 \end{gathered}$$

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