Speed, Time and Distance


  1. Two donkeys are standing 400 metres apart. First donkey can run at a speed of 3 m/sec and the second can run at 2 m/sec. If two donkeys run towards each other after how much time (in seconds) will they bump into each other?









  1. View Hint View Answer Discuss in Forum

    Distance between both donkeys = 400 metre.
    Relative speed = (3 + 2) m./sec. = 5 m./sec.

    ∴  Required time =
    Distance
    Relative speed

    =
    400
    = 80 seconds
    5

    Correct Option: B

    Distance between both donkeys = 400 metre.
    Relative speed = (3 + 2) m./sec. = 5 m./sec.

    ∴  Required time =
    Distance
    Relative speed

    =
    400
    = 80 seconds
    5


  1. A man travels for 14 hours 40 minutes. He covers half of the journey by train at the rate of 60 km/hr and rest half by road at the rate of 50 km/hr. The distance travelled by him is :









  1. View Hint View Answer Discuss in Forum

    Let total distance covered be 2x km.
    Total time = 14 hours 40 minutes

    = 14
    40
    hours = 14
    2
    hours
    603

    =
    44
    hours
    3

    Time =
    Distance
    Speed

    According to the question,
    x
    +
    x
    =
    44
    60503

    ∴ 
    5x + 6x
    =
    44
    3003

    ⇒ 
    11x
    =
    44
    3003

    ⇒  x =
    44
    ×
    300
    = 400
    311

    ∴  Total distance
    = 2x = 2 × 400 = 800 km

    Correct Option: B

    Let total distance covered be 2x km.
    Total time = 14 hours 40 minutes

    = 14
    40
    hours = 14
    2
    hours
    603

    =
    44
    hours
    3

    Time =
    Distance
    Speed

    According to the question,
    x
    +
    x
    =
    44
    60503

    ∴ 
    5x + 6x
    =
    44
    3003

    ⇒ 
    11x
    =
    44
    3003

    ⇒  x =
    44
    ×
    300
    = 400
    311

    ∴  Total distance
    = 2x = 2 × 400 = 800 km



  1. Sound travels 330 metre in a second.When the sound follows the flash of lightning after 10 seconds the thunder cloud will be at a distance of :









  1. View Hint View Answer Discuss in Forum

    Distance = Speed × Time
    = 330 × 10 = 3300 metre

    Correct Option: D

    Distance = Speed × Time
    = 330 × 10 = 3300 metre


  1. A man travelled a distance of 61 km. in 9 hours, partly by walking at the speed of 4 km./hr. and partly on bicycle at the speed of 9 km./hr. The distance covered by walking is









  1. View Hint View Answer Discuss in Forum

    Let the distance covered on foot be x km.
    ∴  Distance covered on cycle = (61 – x) km.

    Time =
    Distance
    Speed

    ∴ 
    x
    +
    61 − x
    = 9
    49

    ⇒  
    x
    x
    = 9 −
    61
    499

    ⇒  
    9x − 4x
    =
    81 − 61
    369

    ⇒  
    5x
    =
    20
    369

    ⇒   x =
    20
    ×
    36
    = 16 km.
    95

    Correct Option: A

    Let the distance covered on foot be x km.
    ∴  Distance covered on cycle = (61 – x) km.

    Time =
    Distance
    Speed

    ∴ 
    x
    +
    61 − x
    = 9
    49

    ⇒  
    x
    x
    = 9 −
    61
    499

    ⇒  
    9x − 4x
    =
    81 − 61
    369

    ⇒  
    5x
    =
    20
    369

    ⇒   x =
    20
    ×
    36
    = 16 km.
    95



  1. A farmer travelled a distance of 61 km in 9 hours. He travelled partly on foot at a speed of 4 km/hour and partly on bicycle at a speed of 9 km/hour. The distance travelled on foot is :









  1. View Hint View Answer Discuss in Forum

    Length of journey on foot = x km. (let).
    ∴  Length of journey on cycle = (61 – x ) km.
    According to the question,

    Time =
    Distance
    Speed

    ∴ 
    x
    +
    61 − x
    = 9
    49

    ⇒ 
    9x + 244 − 4x
    = 9
    36

    ⇒  5x + 244 = 36 × 9 = 324
    ⇒  5x = 324 – 244 = 80
    ⇒  x =
    80
    = 16 km
    5

    Correct Option: B

    Length of journey on foot = x km. (let).
    ∴  Length of journey on cycle = (61 – x ) km.
    According to the question,

    Time =
    Distance
    Speed

    ∴ 
    x
    +
    61 − x
    = 9
    49

    ⇒ 
    9x + 244 − 4x
    = 9
    36

    ⇒  5x + 244 = 36 × 9 = 324
    ⇒  5x = 324 – 244 = 80
    ⇒  x =
    80
    = 16 km
    5