Question

Two trains start from the same station at 11:00 p.m. in opposit directions at the speed of 72 km/h and 63 km/h, respectivly . At what time they will be 810 km apart

Answer 1

Find Total Speed:

1 hour = 72 + 63

1 hour = 135 km

⇒ Speed = 135 km/h

Find the time needed:

Distance = 810 km

Speed = 135 km/h

Time = Distance ÷ Speed

Time = 810 ÷ 135 = 6 hours

Find the time that they will be 810 km apart:

11.00 pm + 6 hours = 5.00 am

Answer: The time will be 5.00am