Speed, Time and Distance


  1. A train moves with a speed of 30 kmph for 12 minutes and for next 8 minutes at a speed of 45 kmph. Find the average speed of the train:
    1. 37.5 kmph
    2. 36 kmph
    3. 48 kmph
    4. 30 kmph

  1. View Hint View Answer Discuss in Forum

    Average speed =
    Total distance
    time taken

    = 30 ×
    12
    + 45 ×
    8
    6060
    12
    +
    8
    6060

    = 12 × 3 = 36 kmph

    Correct Option: B

    Average speed =
    Total distance
    time taken

    = 30 ×
    12
    + 45 ×
    8
    6060
    12
    +
    8
    6060

    = 12 × 3 = 36 kmph


  1. A person travels 600 km by train at 80km/hr, 800 km by ship at 40 km/hr 500 km by aeroplane at 400 km/hr and 100 km by car at 50km/hr. What is the average speed for the entire distance ?
    1. 65
      5
      km./hr.
      123
    2. 60 km./hr.
    3. 60
      5
      km./hr.
      123
    4. 62 km./hr.

  1. View Hint View Answer Discuss in Forum

    Total time =
    600
    +
    800
    +
    500
    +
    100
    804040050

    =
    246
    hours.
    8

    Average speed =
    600 + 800 + 500 +100
    246
    8

    =
    2000 × 8
    246

    = 65
    5
    km/hr.
    123

    Correct Option: A

    Total time =
    600
    +
    800
    +
    500
    +
    100
    804040050

    =
    246
    hours.
    8

    Average speed =
    600 + 800 + 500 +100
    246
    8

    =
    2000 × 8
    246

    = 65
    5
    km/hr.
    123



  1. A boy rides his bicycle 10km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately :
    1. 10.4 km/hr
    2. 10.8 km/hr
    3. 11.0 km/hr
    4. 12.2 km/hr

  1. View Hint View Answer Discuss in Forum

    Total distance = 10 + 12 = 22 km

    Total time =
    10
    +
    12
    1210

    =
    244
    hours
    120

    ∴  Required average speed =
    Total distance
    Total time

    =
    22
    244
    120

    =
    22
    × 120 = 10.8 km/hr.
    244


    Second Method :
    Here, d1 = 10, S1 = 12
    d2 = 12, S2 = 10
    Average Speed =
    d1 + d2
    d1
    +
    d2
    S1S2

    =
    10 + 12
    10
    +
    12
    1210

    =
    22 × 120
    = 10.8 km/hrs.
    244

    Correct Option: B

    Total distance = 10 + 12 = 22 km

    Total time =
    10
    +
    12
    1210

    =
    244
    hours
    120

    ∴  Required average speed =
    Total distance
    Total time

    =
    22
    244
    120

    =
    22
    × 120 = 10.8 km/hr.
    244


    Second Method :
    Here, d1 = 10, S1 = 12
    d2 = 12, S2 = 10
    Average Speed =
    d1 + d2
    d1
    +
    d2
    S1S2

    =
    10 + 12
    10
    +
    12
    1210

    =
    22 × 120
    = 10.8 km/hrs.
    244


  1. A car moving in the morning fog passes a man walking at 4 km/h. in the same direction. The man can see the car for 3 minutes and visibility is upto a distance of 130 m. The speed of the car is :
    1. 7
      3
      km. per hour
      5
    2. 6
      3
      km. per hour
      5
    3. 7 km. per hour
    4. 5 km. per hour

  1. View Hint View Answer Discuss in Forum

    Speed of car = x kmph.
    Relative speed = (x – 4) kmph.

    Time = 3 minutes =
    3
    hours =
    1
    hours
    6020

    Distance = 130 metre
    =
    130
    km. =
    13
    km.
    1000100

    ∴  Relative speed =
    Distance
    Time

    ⇒  x – 4 =
    13
    × 20
    100

    ⇒  5x – 20 = 13
    ⇒  5x = 20 + 13 = 33
    ⇒  x =
    33
    = 6
    3
    kmph.
    55

    Correct Option: B

    Speed of car = x kmph.
    Relative speed = (x – 4) kmph.

    Time = 3 minutes =
    3
    hours =
    1
    hours
    6020

    Distance = 130 metre
    =
    130
    km. =
    13
    km.
    1000100

    ∴  Relative speed =
    Distance
    Time

    ⇒  x – 4 =
    13
    × 20
    100

    ⇒  5x – 20 = 13
    ⇒  5x = 20 + 13 = 33
    ⇒  x =
    33
    = 6
    3
    kmph.
    55



  1. A car covers a certain distance in 25 hours.
    If it reduces the speed by
    1
    th,the car covers 200 km.
    5
    less in that time. The speed of car is
    1. 60 km./hr.
    2. 30 km./hr.
    3. 40 km./hr.
    4. 50 km./hr.

  1. View Hint View Answer Discuss in Forum

    Speed of car = x kmph.
    ∴  Distance = Speed × Time
    = 25x km.
    Case II,

    Speed of car =
    4x
    kmph.
    5

    Distance covered =
    4x
    × 25
    5

    = 20x km.
    According to the question,
    25x – 20x = 200
    ⇒  5x = 200
    ⇒  x =
    200
    = 40 kmph.
    5

    Correct Option: C

    Speed of car = x kmph.
    ∴  Distance = Speed × Time
    = 25x km.
    Case II,

    Speed of car =
    4x
    kmph.
    5

    Distance covered =
    4x
    × 25
    5

    = 20x km.
    According to the question,
    25x – 20x = 200
    ⇒  5x = 200
    ⇒  x =
    200
    = 40 kmph.
    5