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A train travels from station A to station B. If the train leaves station A and makes 75 km/hr, it arrives at station B 48 minutes ahead of scheduled. If it made 50 km/hr, then by the scheduled time of arrival it would still have 40 km more to go to station B. Find:
A) The distance between the two stations;
B) The time it takes the train to travel from A to B according to the schedule;
C) The speed of the train when it's on schedule.

Respuesta :

mhanifa

Answer:

  • A) 290 km
  • B) 4 hours
  • C) 72.5 km/h

Step-by-step explanation:

Let distance be d and time t

At 75 km/h speed the distance is

  • d = 75(t - 48 min) = 75(t - 48/60 hours)

At 50 km/h speed the distance is

  • d = 50t + 40

Since the distance is same, we get the equation:

  • 75(t - 48/60) = 50t + 40
  • 75t - 75*4/5 = 50t + 40
  • 75t - 60 = 50t + 40
  • 75t - 50t = 40 + 60
  • 25t = 100
  • t = 4 hours

A) The distance between A and B

  • d = 50*5 + 40 = 290 km

B) Time is

  • 4 hours as found above

C) The speed = d/t

  • Speed = 290/4 = 72.5 km/h

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