Speed, Time and Distance


  1. A moving train passes a platform 50 metres long in 14 seconds and a lamp-post in 10 seconds. The speed of the train is
    1. 24 km/hr.
    2. 36 km/hr.
    3. 40 km/hr.
    4. 45 km/hr.

  1. View Hint View Answer Discuss in Forum

    Suppose length of train be x
    According to question

    x + 50
    =
    x
    1410

    ⇒  14x = 10x + 500
    ⇒  4x = 500
    ⇒  x =
    500
    = 125 m
    4

    Therefore, speed
    =
    125
    ×
    18
    = 45 kmph
    105

    Correct Option: D

    Suppose length of train be x
    According to question

    x + 50
    =
    x
    1410

    ⇒  14x = 10x + 500
    ⇒  4x = 500
    ⇒  x =
    500
    = 125 m
    4

    Therefore, speed
    =
    125
    ×
    18
    = 45 kmph
    105


  1. A person standing on a railway platform noticed that a train took 21 seconds to completely pass through the platform which was 84 m long and it took 9 seconds in passing him. The speed of the train was
    1. 25.2 km/hour
    2. 32.4 km/hour
    3. 50.4 km/hour
    4. 75.6 km/hour

  1. View Hint View Answer Discuss in Forum

    Let the length of train be x metres.
    When the train crosses the standing man,

    its speed =
    x
    9

    When the train crosses the platform of length 84 m, its speed
    =
    x + 84
    21

    Obviously,  
    x
    =
    x + 84
    921

    ⇒  21x – 9x = 9 × 84
    ⇒  12x = 9 × 84
    ⇒  x =
    9 × 84
    = 63 m
    12

    ∴   Required speed =
    63
    m/sec
    9

    =
    63
    ×
    18
    kmph = 25.2 kmph
    95

    Correct Option: A

    Let the length of train be x metres.
    When the train crosses the standing man,

    its speed =
    x
    9

    When the train crosses the platform of length 84 m, its speed
    =
    x + 84
    21

    Obviously,  
    x
    =
    x + 84
    921

    ⇒  21x – 9x = 9 × 84
    ⇒  12x = 9 × 84
    ⇒  x =
    9 × 84
    = 63 m
    12

    ∴   Required speed =
    63
    m/sec
    9

    =
    63
    ×
    18
    kmph = 25.2 kmph
    95



  1. A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train ?
    1. 69.5 km/hr
    2. 70 km/hr
    3. 79 km/hr
    4. 79.2 km/hr

  1. View Hint View Answer Discuss in Forum

    Let the length of train be x metres.
    Then, speed of train when it

    passes a telegraph post =
    x
    m/sec.
    8

    and speed of train, when it
    passes the bridge =
    x + 264
    20

    Clearly,
    x
    =
    x + 264
    820

    ⇒ 
    x
    =
    x + 264
    25

    ⇒  5x = 2x + 528
    ⇒  3x = 528
    ⇒  x =
    528
    = 176m
    3

    ∴   Speed of train =
    176
    = 22 m/sec.
    8

    = 22 ×
    18
    Kmph
    5

    = 79.2 kmph

    Correct Option: D

    Let the length of train be x metres.
    Then, speed of train when it

    passes a telegraph post =
    x
    m/sec.
    8

    and speed of train, when it
    passes the bridge =
    x + 264
    20

    Clearly,
    x
    =
    x + 264
    820

    ⇒ 
    x
    =
    x + 264
    25

    ⇒  5x = 2x + 528
    ⇒  3x = 528
    ⇒  x =
    528
    = 176m
    3

    ∴   Speed of train =
    176
    = 22 m/sec.
    8

    = 22 ×
    18
    Kmph
    5

    = 79.2 kmph


  1. A train passes a man standing on a platform in 8 seconds and also crosses the platform which is 264 metres long in 20 seconds. The length of the train (in metres) is :
    1. 188
    2. 176
    3. 175
    4. 96

  1. View Hint View Answer Discuss in Forum

    Rule 10 and Rule 1,
    Let length of train be x m

    ∴   Speed of train =
    x + 264
    20

    Also, speed of train =
    x
    8

    Obviously,  
    x
    =
    x + 264
    820

    ⇒  
    x
    =
    x + 264
    25

    ⇒  5x = 2x + 528
    ⇒  5x – 2x = 528
    ⇒  x = 528 ÷ 3 = 176 m

    Correct Option: B

    Rule 10 and Rule 1,
    Let length of train be x m

    ∴   Speed of train =
    x + 264
    20

    Also, speed of train =
    x
    8

    Obviously,  
    x
    =
    x + 264
    820

    ⇒  
    x
    =
    x + 264
    25

    ⇒  5x = 2x + 528
    ⇒  5x – 2x = 528
    ⇒  x = 528 ÷ 3 = 176 m



  1. A train passes a 50 metres long platform in 14 seconds and a man standing on the platform in 10 seconds.The speed of the train is :
    1. 24 km/hr
    2. 36 km/hr
    3. 40 km/hr
    4. 45 km/hr

  1. View Hint View Answer Discuss in Forum

    Rule 10 and Rule 1,
    Let the length of train be x metres
    ∴  According to question

    Speed of the train =
    x
    m/sec.
    10

    Also, the speed of the train
    =
    x + 50
    m/sec.
    14

    [∵  It passes the platform in 14 seconds]
    Both the speeds should be equal,
    i.e.,
    x
    =
    x + 50
    1014

    or 14x = 10x + 500
    or 14x – 10x = 500
    or 4x = 500
    ∴  x = 125 metres
    Hence, Speed =
    125
    = 12 5. m/sec.
    10

    =
    12.5 × 18
    km/hr.
    5

    = 45 km/hr.

    Correct Option: D

    Rule 10 and Rule 1,
    Let the length of train be x metres
    ∴  According to question

    Speed of the train =
    x
    m/sec.
    10

    Also, the speed of the train
    =
    x + 50
    m/sec.
    14

    [∵  It passes the platform in 14 seconds]
    Both the speeds should be equal,
    i.e.,
    x
    =
    x + 50
    1014

    or 14x = 10x + 500
    or 14x – 10x = 500
    or 4x = 500
    ∴  x = 125 metres
    Hence, Speed =
    125
    = 12 5. m/sec.
    10

    =
    12.5 × 18
    km/hr.
    5

    = 45 km/hr.