Cost reduction

Fourteen pieces of goods cost just as much as 21 pieces before the discount. The price of one piece after the discount is CZK 1.50 lower than before the price reduction. How much was one piece before the discount?

Final Answer:

x =  4.5 Kc

Step-by-step explanation:

$$\begin{gathered} 14x=21\cdot y \\ y=x-1.5 \\ 14\cdot x=21\cdot y \\ y=x-1.5 \\ 14x-21y=0 \\ x-y=1.5 \\ Row2-\frac{1}{14}\cdot Row1\to Row2 \\ 0.5y=1.5 \\ y=\frac{1.5}{0.5}=3 \\ x=\frac{0+21y}{14}=\frac{0+21\cdot 3}{14}=4.5=4.5\text{Kc} \\ x=\frac{9}{2}=4.5 \\ y=3 \end{gathered}$$

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