question_answer

A train starts from station A and reaches station D which is 150 km away. It has scheduled halts at station B and C for 5 minutes each. The distance between A and B is 50 km and C and D is 60 km. The train starts at 5 p.m. from A and reaches D at 8.30 p.m. What is its average speed in\[m\,{{s}^{-1}}?\]

A) \[11.88\,m\,{{s}^{-1}}\]                

B) \[15.4\,m\,{{s}^{-1}}\]  

C)        \[8.41\text{ }m\text{ }{{s}^{-1}}\]      

D)        \[5.83\text{ }m\text{ }{{s}^{-1}}\]                           

Correct Answer: A

Solution :

Average speed \[\text{=}\frac{\text{Total}\,\text{distance}\,\text{travelled}}{\text{Toital}\,\text{time}\,\text{taken}}\] Total distance = 150 km Total time taken = 3.5 hour \[\therefore \]Average speed \[=\frac{150}{3.5}=42.8\,km\,{{h}^{-1}}\] Average speed is \[m\,{{s}^{-1}}\] \[=\frac{42.8\times 1000}{60\times 60}=11.88\,m\,{{s}^{-1}}\]