Speed, Time and Distance

  1. A and B are 20 km apart. A can walk at an average speed of 4 km/hr and B at 6 km/h. If they start walking towards each other at 7:000 am, when they will meet?
    1. 8:00 am
    2. 8:30 am
    3. 9:00 am
    4. 10:00 am
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    Sum of distance traveled by them after T hours
    6T + 4T = 20 KM
    T = 2 hours.

    Correct Option: C

    Suppose they will meet after T hours.
    Distance = Speed x Time
    Sum of distance traveled by them after T hours
    6T + 4T = 20 km
    T = 2 hours.
    So they will meet at 7:00 AM + 2 hours = 9:00 AM

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  1. Arjun runs a distance of 1500 m in 5 minutes. What is his speed in Km/hr ?
    1. 16 km/hr
    2. 18 km/hr
    3. 15 km/hr
    4. 20 km/hr
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    Speed in Km/hr = Speed in m/sec x 18/5

    Correct Option: B

    Speed = (1500/300 ) m/sec
    = 5 m/sec
    = (5 x 18/5 ) km/hr
    = 18 km/hr

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  1. In how many minutes will Rohit cover a distance of 800 m, if he runs at speed of 10 km/hr?
    1. 5 min 12 sec
    2. 4 min 40 sec
    3. 5 min
    4. 4 min 48 sec
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    Speed in m/sec = Speed in km/hr x 5/18

    Correct Option: D

    Rohit's speed = 10 Km/hr = (10 x 5/18) m/sec = 50/18 m/sec

    Time taken to cover 800 m = (800 / (50/18) ) sec
    = (800 x 18/50) sec = 288 sec = 4 min 48 sec

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  1. A plane flies along the four sides of a square field at a speed of 200, 400, 600 and 800 km/hr. Then find the average speed of plane around the square field.
    1. 394
    2. 400
    3. 414
    4. 384
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    Let the side of the square field be x and the speed of plane be y

    x/200 + x/400 + x/600 + x/800 = 4x/y

    Correct Option: D

    Let the side of the square field be x and the average speed of plane be y

    x/200 + x/400 + x/600 + x/800 = 4x/y
    ⇒ 25x/2400 = 4x/y
    ⇒ y =384

    ∴ Average speed is 384 km/hr

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  1. Laxman has to cover a distance of 6 km in 45 minutes . If he cover one half of the distance in 2/3rd time . what should be his speed to cover the remaining distance in the remaining time?
    1. 12 km/hr.
    2. 16 km/hr.
    3. 3 km/hr.
    4. 8 km/hr.
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    ∵ Time left = (1/3 X 45/60) hr.
    = 1/4 hr.
    Distance left = 3km

    ∴ speed required = [3 / (1/4) ] km/hr.

    Correct Option: C

    ∵ Time left = (1/3 X 45/60) hr.
    = 1/4 hr.
    Distance left = 3km

    ∴ speed required = [3 / (1/4) ] km/hr.
    = 3 x 4
    =12km/hr .

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