## Speed, Time and Distance

#### Speed, Time and Distance

1. A train passes two bridges of lengths 500 m and 250 m in 100 seconds and 60 seconds respectively. The length of the train is :
1. 152 m
2. 125 m
3. 250 m
4. 120 m

1. Length of train = x metre (let)

 Speed of train= (Length of train and bridge) Time taken in crossing

 ⇒ x + 500 = x + 250 100 60

 ⇒ x + 500 = x + 250 5 3

⇒  5x + 1250 = 3x + 1500
⇒  5x – 3x = 1500 – 1250
⇒  2x = 250
 ⇒  x = 250 = 125 metre 2

##### Correct Option: B

Length of train = x metre (let)

 Speed of train= (Length of train and bridge) Time taken in crossing

 ⇒ x + 500 = x + 250 100 60

 ⇒ x + 500 = x + 250 5 3

⇒  5x + 1250 = 3x + 1500
⇒  5x – 3x = 1500 – 1250
⇒  2x = 250
 ⇒  x = 250 = 125 metre 2

1. A 200 metre long train is running at a speed of 72 km/hr. How long will it take to cross 800metre long bridge ?
1. 50 seconds
2. 40 seconds
3. 60 seconds
4. 30 seconds

1. Speed of train = 72 kmph

 = 72 × 5 m/sec. 18

= 20 m/sec.
 Required time= Length of train and bridge Speed of train

 = (200 + 800) 20

 = 1000 = 50 seconds 20

##### Correct Option: A

Speed of train = 72 kmph

 = 72 × 5 m/sec. 18

= 20 m/sec.
 Required time= Length of train and bridge Speed of train

 = (200 + 800) 20

 = 1000 = 50 seconds 20

1. If a man running at 15 kmph crosses a bridge in 5 minutes, the length of the bridge is
1. 1000 metres
2. 500 metres
3. 750 metres
4. 1250 metres

1. Time = 5 minutes

 = 1 hour 12

∴  Length of bridge = Speed × Time
 = 15 × 1 = 5 km. 12 4

 = 5 × 1000 metre 4

= 1250 metre

##### Correct Option: D

Time = 5 minutes

 = 1 hour 12

∴  Length of bridge = Speed × Time
 = 15 × 1 = 5 km. 12 4

 = 5 × 1000 metre 4

= 1250 metre

1. How many seconds will a train 120 metre long running at the rate of 36 km/hr take to cross a bridge of 360 metres in length ?
1. 48 sec
2. 40 sec
3. 46 sec
4. 36 sec

1. Speed of train = 36 kmph

 = 36 × 5 m/sec. 18

= 10 m/sec
 Required time= Length of train and bridge Speed of train

 = 120 + 360 = 480 = 48 seconds 10 10

##### Correct Option: A

Speed of train = 36 kmph

 = 36 × 5 m/sec. 18

= 10 m/sec
 Required time= Length of train and bridge Speed of train

 = 120 + 360 = 480 = 48 seconds 10 10

1. A train 50 metre long passes a platform 100 metre long in 10 seconds. The speed of the train in km/hr is
1. 10
2. 54
3. 15
4. 100

1.  Speed of train = Length of platform and train Time taken to crossing

 = 100 + 50 metre/second 10

= 15 metre/second
 = 15 × 18 kmph 5

= 54 kmph

##### Correct Option: B

 Speed of train = Length of platform and train Time taken to crossing

 = 100 + 50 metre/second 10

= 15 metre/second
 = 15 × 18 kmph 5

= 54 kmph