CLAT CLAT Solved Paper-2010

  • question_answer
    Directions From the four answers given, shade the appropriate answer in the space provided for it on the OW Answer Sheet.
    A person takes 3 h to walk a certain distance and riding back. He could walk both ways in 5 h. How long could it take to ride both ways.

    A) 1.5h                            

    B) 1h     

    C) 0.5h                            

    D) 2 h

    Correct Answer: B

    Solution :

    Ans.     Suppose that person can walk at x km/h and he can ride at\[y\]. So, the average speed \[=\frac{2xy}{x+y}km/h\] Suppose the total distance is A Now, he is only walking. So, average speed \[=x\,km/h\] Total time \[=\frac{2A}{x}\] \[\Rightarrow \]            \[=\frac{2A}{x}\,\,5h\] \[\Rightarrow \]            \[A\,\,2.5x\,km\] Now, when he is going on walk and riding back. Then, total time \[\frac{\text{Distance}}{\text{Speed}}\]walking time + riding time = 3 \[\Rightarrow \]            \[\frac{2.5}{x}+\frac{2.5x}{y}=3\] \[\Rightarrow \]            \[2.5+\frac{2.5x}{y}=3\] \[\Rightarrow \]            \[\frac{2.5x}{y}=0.5\] \[\Rightarrow \]            \[\frac{x}{y}=\frac{0.5}{2.5}\] \[\Rightarrow \]            \[\frac{x}{y}=\frac{1}{5}\] or         \[y=5x\] So, riding is 5 times farther then walking and it requires 5 times lesser time than walking. As it requires 5 h to walk both side. So, it requires 1 h to ride both side.

adversite


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