Q. A journey takes 4 hours 30 minutes at a speed of 60 km/hr. If the speed is 15 m/s, then the journey will take :
Answer: 5 hours
Notes: $latex 60\ km/hr = 60\times \frac{5}{18}\ m/s = \frac{50}{3}\ m/s&s=1$ $latex \therefore\ Speed \propto \frac{1}{Time}&s=1$ $latex => S_{1}\times T_{1} = S_{2}\times T_{2}$ $latex => \frac{50}{3}\times \frac{9}{2} = 15\times T_{2}&s=1$ $latex => 75 = 15\times T_{2}$ $latex => T_{2} = \frac{75}{15} = 5\ hours&s=1$ Hence option [A] is correct answer.

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