11. A boy runs 20 km in 2.5 hours. How long will he take to run 32 km at double the previous speed ?

1. 1. 2 hours

   
   
   

   2. 2	1	hours
      	2

   
   
   

   3. 4	1	hours
      	2

   
   
   

   4. 5 hours

   
   
   

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1. View Hint View Answer Discuss in Forum

   The boy covers 20 km in 2.5 hours.
   

   ⇒ Speed =	20	= 8 km/hr.
   	2.5

   
   New speed = 16 km/hr
   

   ∴ Time =	32	= 2 hours.
   	16

   Correct Option: A

   The boy covers 20 km in 2.5 hours.
   

   ⇒ Speed =	20	= 8 km/hr.
   	2.5

   
   New speed = 16 km/hr
   

   ∴ Time =	32	= 2 hours.
   	16

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12. A train is moving with the speed of 180 km/hr. Its speed (in metres per second) is :

1. 1. 5

   
   
   

   2. 40

   
   
   

   3. 30

   
   
   

   4. 50

   
   
   

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1. View Hint View Answer Discuss in Forum

   Speed = 180 kmph
   

   =	180 × 5	m/sec = 50 m/sec
   	18

   
   

   	∵   1 km/hr =	5	m/s
   		18

   Correct Option: D

   Speed = 180 kmph
   

   =	180 × 5	m/sec = 50 m/sec
   	18

   
   

   	∵   1 km/hr =	5	m/s
   		18

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13. A man riding his bicycle covers 150 metres in 25 seconds. What is his speed in km per hour ?

1. 1. 25

   
   
   

   2. 21.6

   
   
   

   3. 23

   
   
   

   4. 20

   
   
   

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1. View Hint View Answer Discuss in Forum

   Speed =	150	= 6 m/sec
   	25

   
   

   = 6 ×	18	=	108	= 21.6 kmph
   	5		5

   Correct Option: B

   Speed =	150	= 6 m/sec
   	25

   
   

   = 6 ×	18	=	108	= 21.6 kmph
   	5		5

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14. A and B travel the same distance at speed of 9 km/hr and 10 km/hr respectively. If A takes 36 minutes more than B, the distance travelled by each is

1. 1. 48 km

   
   
   

   2. 54 km

   
   
   

   3. 60 km

   
   
   

   4. 66 km

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let the distance between A and B be x km, then
   

   x	−	x	=	36	=	3
   9		10		60		5

   
   

   ⇒	x	=	3
   	90		5

   
   

   ⇒ x =	3	× 90 = 54 km.
   	5

   
   
   Second Method :
   Here, S₁ = 9, t₁ = x
   

   S2 = 10, t2 = x −	36
   	60

   
   S₁t₁ = S₂t₂
   

   9 × x = 10		x −	36
   			60

   
   9x = 10x – 6x = 6
   Distance travelled
   = 9 × 6 = 54 km
   

   Correct Option: B

   Let the distance between A and B be x km, then
   

   x	−	x	=	36	=	3
   9		10		60		5

   
   

   ⇒	x	=	3
   	90		5

   
   

   ⇒ x =	3	× 90 = 54 km.
   	5

   
   
   Second Method :
   Here, S₁ = 9, t₁ = x
   

   S2 = 10, t2 = x −	36
   	60

   
   S₁t₁ = S₂t₂
   

   9 × x = 10		x −	36
   			60

   
   9x = 10x – 6x = 6
   Distance travelled
   = 9 × 6 = 54 km
   

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15. A person started his journey in the morning.

    At 11 a.m. he covered	3	of the journey and on the
    	8

    same day at 4.30 p.m. he covered	5	of the journey.
    	6

    
    He started his journey at

1. 1. 6.00 a.m.

   
   
   

   2. 3.30 a.m.

   
   
   

   3. 7.00 a.m.

   
   
   

   4. 6.30 a.m.

   
   
   

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1. View Hint View Answer Discuss in Forum

   Difference of time = 4.30 p.m – 11.a.m.
   

   = 5	1	hours =	11	hours
   	2		2

   
   

   Distance covered in	11	hrs
   	2

   
   

   =	5	−	3	=	20 − 9	=	11	part
   	6		8		24		24

   
   

   ∵	11	part of the journey is covered in	11	hours
   	24		2

   
   

   ⇒	3	part of the journey is covered in
   	8

   
   

   =	11	×	24	×	3	=	9	hours
   	2		11		8		2

   
   

   = 4	1	hours.
   	2

   
   Clearly the person started at 6.30 a.m.

   Correct Option: D

   Difference of time = 4.30 p.m – 11.a.m.
   

   = 5	1	hours =	11	hours
   	2		2

   
   

   Distance covered in	11	hrs
   	2

   
   

   =	5	−	3	=	20 − 9	=	11	part
   	6		8		24		24

   
   

   ∵	11	part of the journey is covered in	11	hours
   	24		2

   
   

   ⇒	3	part of the journey is covered in
   	8

   
   

   =	11	×	24	×	3	=	9	hours
   	2		11		8		2

   
   

   = 4	1	hours.
   	2

   
   Clearly the person started at 6.30 a.m.

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