Q17 of 54 Page 77

A man travels 370 km partly by train and partly by car. If he covers 250 km by train and the rest by car it takes him 4 hours but if he travels 130km by train and the rest by the car he takes 18 min. longer. Find the speed of the train and car.

Total distance = 370 km

Case 1


Distance covered by train = 250 km


Distance covered by car = total distance - distance traveled by train


= 370 – 250


= 120 km


Total time = 4 hours


Let the speed of train be x km/hr and the speed of car be y km/hr.






Total time taken = time taken for train’s journey + time taken for car's journey


…….(1)


Case 2


Distance covered by train = 130 km


Distance covered by car = Total distance – distance covered by train


= 320 – 130


= 240 km


Time = time taken in Case 1 + 18 minutes


= 4 hrs + 18 min


Converting 18 minute to hours


60 min = 1 hr



For 18 minutes





= 4.3 hrs


Let speed of train = x km/hr


The speed of car = y km/hr






Total time took = time taken for train's journey + time taken for car's journey


……(2)


Eliminate (1) and (2)




Let,


(250a + 120b = 4) ……multiply by 2


(130a + 240b = 4.3) ……multiply by 1



370a = 3.7





x = 100







y = 80


Therefore, the speed of the train is 100 km per hour and the speed of the car is 80 km per hour.


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