A train covers half of its journey at a speed of 10 ms–1 and the other half at a speed of 15 ms–1. What is the average speed of the train during the whole journey?

Engineering

Physics

Reflection from spherical mirror

Question

A train covers half of its journey at a speed of 10 ms^–1 and the other half at a speed of 15 ms^–1. What is the average speed of the train during the whole journey?

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t₁ = $(\frac{x / 2}{10})$ , t₂ = $(\frac{x / 2}{15})$
t₁ = x/20, t₂ = x/30
total time = t₁ + t₂ = $\frac{x}{20} + \frac{x}{30} = \frac{x}{12}$
Average speed = $\frac{total distance}{total time} = \frac{X}{(X / 12)}$ = 12 m/s

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