16. The speed of a bus is 72 km/hr. The distance covered by the bus in 5 seconds is

1. 1. 100 m

   
   
   

   2. 60 m

   
   
   

   3. 50 m

   
   
   

   4. 74.5 m

   
   
   

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1. View Hint View Answer Discuss in Forum

   Speed of bus = 72 kmph
   

   =		72 × 5		metre/second
   		18

   
   = 20 metre/second
   ∴  Required distance
   = 20 × 5 = 100 metre

   Correct Option: A

   Speed of bus = 72 kmph
   

   =		72 × 5		metre/second
   		18

   
   = 20 metre/second
   ∴  Required distance
   = 20 × 5 = 100 metre

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17. Two men start together to walk a certain distance, one at 4 km/h and another at 3 km/h. The former arrives half an hour before the latter. Find the distance.

1. 1. 8 km

   
   
   

   2. 7 km

   
   
   

   3. 6 km

   
   
   

   4. 9 km

   
   
   

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1. View Hint View Answer Discuss in Forum

   If the required distance be x km, then
   

   x	−	x	=	1
   3		4		2

   
   

   ⇒	4x − 3x	=	1
   	12		2

   
   

   ⇒	x	=	1	⇒x = 6 km
   	12		2

   
   
   Second Method :
   Here S₁ = 4, t₁ = x
   

   S2 = 3, t2 = x +	1
   	2

   
   S₁t₁ = S₂t₂
   

   4 × x = 3		x +	1
   			2

   
   

   4x – 3x =	3	x =	3
   	2		2

   
   

   Distance =4 ×	3	= 6 kms
   	2

   Correct Option: C

   If the required distance be x km, then
   

   x	−	x	=	1
   3		4		2

   
   

   ⇒	4x − 3x	=	1
   	12		2

   
   

   ⇒	x	=	1	⇒x = 6 km
   	12		2

   
   
   Second Method :
   Here S₁ = 4, t₁ = x
   

   S2 = 3, t2 = x +	1
   	2

   
   S₁t₁ = S₂t₂
   

   4 × x = 3		x +	1
   			2

   
   

   4x – 3x =	3	x =	3
   	2		2

   
   

   Distance =4 ×	3	= 6 kms
   	2

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18. A train starts from a place A at 6 a.m. and arrives at another place B at 4.30 p.m. on the same day. If the speed of the train is 40 km per hour, find the distance travelled by the train ?

1. 1. 420 km

   
   
   

   2. 230 km

   
   
   

   3. 320 km

   
   
   

   4. 400 km

   
   
   

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1. View Hint View Answer Discuss in Forum

   Time = 10	1	hours
   	2

   
   

   =	21	hours
   	2

   
   Speed = 40 kmph
   Distance = Speed × Time
   

   = 40 ×	21	= 420 km
   	2

   Correct Option: A

   Time = 10	1	hours
   	2

   
   

   =	21	hours
   	2

   
   Speed = 40 kmph
   Distance = Speed × Time
   

   = 40 ×	21	= 420 km
   	2

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19. How long does a train, 75 metre long, moving at 60 km/hr take to pass a certain telegraph post?

1. 1. 3.5 seconds

   
   
   

   2. 4.5 seconds

   
   
   

   3. 5 seconds

   
   
   

   4. 5.4 seconds

   
   
   

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1. View Hint View Answer Discuss in Forum

   Distance covered by train = Length of train
   Speed of train = 60 kmph
   

   =		60 × 5		m./sec.
   		18

   
   

   =		50		m./sec.
   		3

   
   

   ∴  Required time =	Distance
   	Speed

   
   

   =		75		seconds
   		(50/3)

   
   

   =	75 × 3	seconds
   	50

   
   = 4.5 seconds

   Correct Option: B

   Distance covered by train = Length of train
   Speed of train = 60 kmph
   

   =		60 × 5		m./sec.
   		18

   
   

   =		50		m./sec.
   		3

   
   

   ∴  Required time =	Distance
   	Speed

   
   

   =		75		seconds
   		(50/3)

   
   

   =	75 × 3	seconds
   	50

   
   = 4.5 seconds

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20. Buses start from a bus terminal with a speed of 20 km/hr at intervals of 10 minutes. What is the speed of a man coming from the opposite direction towards the bus terminal if he meets the buses at intervals of 8 minutes?

1. 1. 3 km/hr

   
   
   

   2. 4 km/hr

   
   
   

   3. 5 km/hr

   
   
   

   4. 7 km/hr

   
   
   

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1. View Hint View Answer Discuss in Forum

   Distance covered in 10 minutes at 20kmph = distance covered in 8 minutes at (20 + x )
   kmph
   

   ⇒  20 ×	10	=	8	(20 + x )
   	60		60

   
   ⇒  200 = 160 + 8x
   ⇒  8x = 40
   

   ⇒  x =	40	= 5 kmph
   	8

   Correct Option: C

   Distance covered in 10 minutes at 20kmph = distance covered in 8 minutes at (20 + x )
   kmph
   

   ⇒  20 ×	10	=	8	(20 + x )
   	60		60

   
   ⇒  200 = 160 + 8x
   ⇒  8x = 40
   

   ⇒  x =	40	= 5 kmph
   	8

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