Let us take the usual speed as \( x \) km/h. From the problem, we get the equation \( \frac{300}{x} - \frac{300}{x+5} = 2 \). Solving this, we get two roots: 25 and -30. We reject -30 because speed cannot be negative in this practical context, just like I cannot sell a bamboo basket of negative size. In my workshop, I also must reject impractical solutions, like using bamboo we cannot afford, even if the maths allows it. So the usual speed is 25 km/h.
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