A) 2 km
B) \[1\frac{1}{2}\,\,km\]
C) 1 km
D) \[1\frac{3}{4}\,\,km\]
Correct Answer: D
Solution :
Let the required distance be x km. Difference of time \[=6+6=12\,\,min\] \[=\frac{12}{60}=\frac{1}{5}h\] According to the question, \[\frac{x}{\frac{5}{2}}-\frac{x}{\frac{7}{2}}=\frac{1}{5}\] \[\Rightarrow \] \[\frac{2x}{5}-\frac{2x}{7}=\frac{1}{5}\] \[\Rightarrow \] \[\frac{14x-10x}{35}=\frac{1}{5}\] \[\Rightarrow \] \[\frac{4x}{35}=\frac{1}{5}\] \[\Rightarrow \] \[x=\frac{35}{4\times 5}=\frac{7}{4}=1\frac{1}{4}\,\,km\]You need to login to perform this action.
You will be redirected in
3 sec