Cake price difference

Mom bought three cakes at the pastry shop. The first cost 72 crowns. The second was a quarter cheaper than the first.
The third dessert was a third of the total price of all three desserts. By how many crowns was the third dessert more expensive than the second?

Final Answer:

x =  9

Step-by-step explanation:

$$\begin{gathered} a=72 \\ b=a-a/4=72-72/4=54 \\ (a+b+c)/3=c \\ a+b+c=3c \\ a+b=2c \\ 72+54=2c \\ 72+54=2\cdot c \\ 2c=126 \\ c=\frac{126}{2}=63 \\ c=63 \\ x=c-b=63-54=9 \end{gathered}$$

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