| Directions From the four answers given, shade the appropriate answer in the space provided for it on the OW Answer Sheet. |
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.
You need to login to perform this action.
You will be redirected in
3 sec
