Long hot dog

In Kostelec above Black Forest, they made a record-long hot dog. When he slowly moved it to the square, one of the spectators decided to measure its length: the size of his footprint was 28 cm; he measured 20 feet in the travel direction and counted 5 feet against the direction. How long was the hot dog?

Correct answer:

X =  350 cm

Step-by-step explanation:

$$\begin{gathered} s=28\text{cm} \\ y=v_{2}t \\ x+y=20 \\ x-y=5 \\ x+y=20 \\ x-y=5 \\ Row2-Row1\to Row2 \\ x+y=20 \\ -2y=-15 \\ y=\frac{-15}{-2}=7.5 \\ x=20-y=20-7.5=12.5 \\ x=\frac{25}{2}=12.5 \\ y=\frac{15}{2}=7.5 \\ X=s\cdot x=28\cdot 12.5=350\text{cm} \end{gathered}$$

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