A distance math problem?

Two trains leave at the same time going in opposite directions. One train is going 72 km/hr and the other is going 68 km/hr. After how long will the trains be 560 km apart?

Comments

  • 68x+72x=560

    solve for x

    x=4

    so 4hr

  • Speed of One Train, R1 = 72 km./hr.

    Speed of Other Train, R2 = 68 km./hr.

    Distance, D = 560 km.

    Since the two trains are moving away from each other,

    Overall Speed, Rt = R1 + R2

    Rt= 72 + 68

    Rt = 140 km./hr.

    D = (Rt)t

    560 = 140t

    t = 560 / 140

    t = 4

    It will take 4 hrs. for the trains to be 560 km. apart.

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  • 560 = distance of train 1 + distance of train 2

    distance = rate * time

    560 = 68t + 72t

    560 = 140t

    4 = t

    Check. After 4 hrs train 1 goes 72*4=288 Km

    Other train goes 68*4= 272 km

    272 + 288 = 560

  • the trains are moving away from eacvh other at 72 + 68 = 140 km/h

    d = rt

    560 = 140t

    t = 4h

  • You have to add the speed together to get the total distance covered in an hour

    72+68=140mph separation

    560/140=4

    4 hours

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