InterviewSolution
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A train travels at a certain average speed for a distance of 63 km and then travels a distance of 72 km at an average speed of 6 km/hr more than its original speed. If it takes 3 hours to complete the total journey, what is the original speed of the train in km/hr?1. 602. 543. 424. 36 |
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Answer» Correct Answer - Option 3 : 42 Given: A train travels at a certain average speed for a distance of 63 km Then travels a distance of 72 km at an average speed of 6 km/hr. more than its original speed. It takes 3 hours to complete the total journey Total distance:63 + 72 = 135 km Total time = 3 hr. Speed = Distance/Time Using formula; Speed is equal to 45 km/hr. The Sum of time for completing 63 km and 72 km must be equal to 3 hr. or 180 min Now, using the option 1) 60 km/h Time for 63 km:63/60 = 1.05 hr. Time for 72km: 72/66= 1.09hr Not equal to 3 hr. 2) 54 km/hr Time for 63 km:63/54= 1.16hr. Time for 72km: 72/60= 1.2hr Not equal to 3 hr. 3) 42 km/hr. Time for 63 km:63/42= 1.5hr. Time for 72km: 72/48= 1.5hr Equal to 3 hr. Hence, Original speed is 42 km/hr. |
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