Justify

50 bottles of red wine are purchased for a company party. In the first store, a bottle of wine costs €6.90. Here they have a promotion that when you buy 4 bottles, the fifth one is free. In the second store, the same bottle of wine costs €8.50. However, they have a 28% discount on wines here. Calculate where it is more profitable to buy wine and justify your decision.

Correct answer:

x = A

Step-by-step explanation:

$$\begin{gathered} n=50 \\ a=6.90\cdot (n-n/5)=6.90\cdot (50-50/5)=276\text{eur} \\ r=100\%-28\%=1-\frac{28}{100}=0.72 \\ b=8.50\cdot n\cdot r=8.50\cdot 50\cdot 0.72=306\text{eur} \\ a<b \\ 276eur<306eur \\ x=A \end{gathered}$$

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