Speed, Time and Distance


  1. A car travelling at a speed of 40 km/hour can complete a journey in 9 hours. How long will it take to travel the same distance at 60 km/hour ?









  1. View Hint View Answer Discuss in Forum

    Total distance covered
    = Speed × Time
    = 40 × 9 = 360 km.
    The required time at 60 kmph

    =
    360
    = 6 hours.
    60


    Second Method :
    Using Rule 9,
    Here, S1 = 40, t1 = 9
    S2 = 60, t2 = ?
    S1t1 = S2t2
    40 × 9 = 60 × t2
    t2 =
    4 × 9
    = 6 hours.
    6

    Correct Option: A

    Total distance covered
    = Speed × Time
    = 40 × 9 = 360 km.
    The required time at 60 kmph

    =
    360
    = 6 hours.
    60


    Second Method :
    Using Rule 9,
    Here, S1 = 40, t1 = 9
    S2 = 60, t2 = ?
    S1t1 = S2t2
    40 × 9 = 60 × t2
    t2 =
    4 × 9
    = 6 hours.
    6


  1. An athlete runs 200 metres race in 24 seconds. His speed (in km/hr) is :









  1. View Hint View Answer Discuss in Forum

    Speed =
    Distance
    Time

    =
    200
    m/s
    24

    200
    m/s =
    10
    ×
    18
    = 30 km/hr.
    24245

    ∵   x m/s =
    18
    x km/hr
    5

    Correct Option: D

    Speed =
    Distance
    Time

    =
    200
    m/s
    24

    200
    m/s =
    10
    ×
    18
    = 30 km/hr.
    24245

    ∵   x m/s =
    18
    x km/hr
    5



  1. A car goes 10 metres in a second. Find its speed in km/hour.









  1. View Hint View Answer Discuss in Forum

    Speed of car = 10 m/sec.
    Required speed in kmph

    =
    10 × 18
    = 36 km/hr
    5

    Correct Option: D

    Speed of car = 10 m/sec.
    Required speed in kmph

    =
    10 × 18
    = 36 km/hr
    5


  1. A man crosses a road 250 metres wide in 75 seconds. His speed in km/hr is :









  1. View Hint View Answer Discuss in Forum

    Speed =
    Distance
    =
    250
    753

    =
    10
    m/sec =
    10
    ×
    18
    km/hr.
    335

    ∵   1 m/s =
    18
    km/hr
    5

    = 2 × 6 km/hr. = 12 km/hr.

    Correct Option: B

    Speed =
    Distance
    =
    250
    753

    =
    10
    m/sec =
    10
    ×
    18
    km/hr.
    335

    ∵   1 m/s =
    18
    km/hr
    5

    = 2 × 6 km/hr. = 12 km/hr.



  1. A man travelled a certain distance by train at the rate of 25 kmph. and walked back at the
    rate of 4 kmph. If the whole journey took 5 hours 48 minutes, the distance was









  1. View Hint View Answer Discuss in Forum

    Let the distance be x km.
    Total time = 5 hours 48 minutes

    = 5 +
    48
    = 5 +
    4
    hours
    605

    =
    29
    hours
    5

    ∴ 
    x
    +
    x
    =
    29
    2545

    ⇒ 
    4x + 25x
    =
    29
    1005

    ⇒  5 × 29x = 29 × 100
    ⇒  x =
    29 × 100
    = 20 km.
    5 × 29


    Second Method :
    Here, x = 25, y = 4
    Average speed =
    2xy
    x + y

    =
    2 × 25 × 4
    =
    200
    25 + 429

    Total Distance =
    200
    × 5
    4
    295

    =
    200
    ×
    29
    = 40 km
    295

    Correct Option: C

    Let the distance be x km.
    Total time = 5 hours 48 minutes

    = 5 +
    48
    = 5 +
    4
    hours
    605

    =
    29
    hours
    5

    ∴ 
    x
    +
    x
    =
    29
    2545

    ⇒ 
    4x + 25x
    =
    29
    1005

    ⇒  5 × 29x = 29 × 100
    ⇒  x =
    29 × 100
    = 20 km.
    5 × 29


    Second Method :
    Here, x = 25, y = 4
    Average speed =
    2xy
    x + y

    =
    2 × 25 × 4
    =
    200
    25 + 429

    Total Distance =
    200
    × 5
    4
    295

    =
    200
    ×
    29
    = 40 km
    295