A) 20 km
B) 10 km
C) 15 km
D) 30 km
Correct Answer: D
Solution :
Let distance be \[x\] km. Time taken to cover \[x\] km at 30 km/hr. \[=\frac{x}{30}hrs\] Time taken to cover x km at 40 km/hr. \[=\frac{x}{40}hrs\] Difference between the time taken \[=15\min =\frac{1}{4}hr\] \[\therefore \frac{x}{30}-\frac{x}{40}=\frac{1}{4}\] \[\frac{40x-30x}{1200}=\frac{1}{4}\] \[\frac{10x}{1200}=\frac{1}{4}\] \[x=\frac{1200}{4\times 10}=30\]You need to login to perform this action.
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