GATE 2026 CE (CE1) – Question 33
The travel times of three vehicles on a 2 km stretch of road are 4, 5, and 8 minutes. Assuming the speed of each vehicle to be constant in this stretch, the Space Mean Speed (in km/h) of the vehicles is ______ (*rounded off to two decimal places*).
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Correct answer: 21.07 to 21.29
Explanation
The speeds are $\frac{2}{4} \times 60 = 30$, $\frac{2}{5} \times 60 = 24$ and $\frac{2}{8} \times 60 = 15$ km/h. The space mean speed is the harmonic mean of these speeds, $\frac{3}{\frac{1}{30} + \frac{1}{24} + \frac{1}{15}} = 21.18$ km/h.