If I walk to my office at 6 km/hr, I arrive 6 minutes early. If however, I walk at 4 km/hr, I arrive 4 minutes late. What is the distance that I walk to reach the office?
- 2 kms
- 2.5 kms
- 3 kms
- 4 kms
- 6 kms
The Usual Method
Let the usual time taken to reach office be ‘t’ hours and distance be ‘4’ kms.
Hence, hours and hours
Estimated Time to arrive at the answer = 45 seconds.
At 6 km/hr it takes th of an hour to travel 1 km
At 4 km/hr it takes th of an hour to travel 1 km
Hence, time difference is hour = 5 minutes.
Actual difference in time = 10 minutes.
If difference in time = 5 minutes for 1 km,
For difference in time = 10 minutes, distance = 2 kms
Estimated Time to arrive at the answer = 15 seconds.