Amarendra and Dharmendra are brothers. One day they start at the same time from their home for Tatanagar railway station in their respective cars. Amarendra took 25 minutes to reach the station. After reaching the station Amarendra found that Dharmendra is 2500 m away from the station. The distance of Tatanagar Station from their home is 15 km. Next day Dharmendra decided to start 7 minutes early. If they drive at the speed same as the previous day then Amarendra will reach the station
Amarendra took 25 minutes to cover 15 km. In the same time Dharmendra travel 2500m less, i,e, 12.5 km
=> Speed of Amarendra = $$\frac{15}{25} = 0.6$$ km/min
Speed of Dharmendra = $$\frac{12.5}{25} = 0.5$$ km/min
=> Time taken by Dharmendra to reach the station = $$\frac{15}{0.5} = 30$$ minutes
Next day, Dharmendra started 7 minutes early, so he will reach the station = 30 - 25 - 7 = -2 minutes
=> 2 minutes or 120 seconds before Amarendra.