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A train travels a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, then it would havetaken 3 hours more to cover the same distance. We need to find the speed of the train |
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Answer» The original speed of the train is 40 km/hour Step-by-step explanation: LET the original speed of the train be X km/hour Distance traveled by the train = 480 km \begin{gathered}\text{Time taken by train = }\FRAC{480}{x}\\\\\text{If the train would have taken 3 hours more then time = }\frac{480}{x-8}\\\\\implies \frac{480}{x}=\frac{480}{x-8}+3\\\\\implies \frac{480}{x}-\frac{480}{x-8}=3\\\\\implies 3x^2-24x+3840=0\\\\\implies x^2-8x+1280=0\\\\\implies \text{ x = -32 or x = 40}\\\\\text{But speed can not be negative }\implies x=40\end{gathered} Time taken by train = x 480
If the train would have taken 3 hours more then time = x−8 480
⟹ x 480
= x−8 480
+3 ⟹ x 480
− x−8 480
=3 ⟹3x 2 −24x+3840=0 ⟹x 2 −8x+1280=0 ⟹ x = -32 or x = 40 But speed can not be negative ⟹x=40
Hence, the original speed of the train is 40 km/hour mark me as brainlist... |
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