Question

a person takes 30min to reach his office from his home at a speed of 6km/h. find the distance between his home and his office.

Answer 1

Ratio of speeds at which he goes to office and returns = 30 : 20 = 3 : 2

Therefore, ratio of the time taken to go to office and returns = 2 : 3 (because time is inversely proportional to speed when distance is constant) 

Total time = 5 hours.
=> Time taken to go to office =5×22+3=2 hr

Hence, distance between house and office = 30 × 2 = 60 km 

Answer 2

Time taken by a person to reach his office from his home = 30 minutes = 1/2 hours
Speed of the person = 6km/h
Distance between the home and the office of the person = Speed × Time = 6 × 1/2 = 3 km