336. A man rides at the rate of 18 km/ hr, but stops for 6 mins. to change horses at the end of every 7th km. The time that he will take to cover a distance of 90 km is

1. 1. 6 hrs.

   
   
   

   2. 6 hrs. 12 min.

   
   
   

   3. 6 hrs. 18 min.

   
   
   

   4. 6 hrs. 24 min.

   
   
   

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1. View Hint View Answer Discuss in Forum

   90 km = 12 × 7km + 6 km. To
   

   cover 7 km total time taken =	7
   	8

   
   

   hours + 6 min. =	88	min. So,
   	3

   
   (12 × 7 km) would be covered in
   

   	12 ×	88		min. and remaining 6 km is	6	hrs or 20 min
   		3			18

   
   

   ∴  Total time =	1056	+ 20
   	3

   
   

   =	1116	hours = 6	1	hours
   	3 × 60		5

   
   = 6 hours 12 minutes.

   Correct Option: B

   90 km = 12 × 7km + 6 km. To
   

   cover 7 km total time taken =	7
   	8

   
   

   hours + 6 min. =	88	min. So,
   	3

   
   (12 × 7 km) would be covered in
   

   	12 ×	88		min. and remaining 6 km is	6	hrs or 20 min
   		3			18

   
   

   ∴  Total time =	1056	+ 20
   	3

   
   

   =	1116	hours = 6	1	hours
   	3 × 60		5

   
   = 6 hours 12 minutes.

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337. A speed of 30.6 km/.hr is the same as

1. 1. 8.5 m/sec.

   
   
   

   2. l0 m/sec.

   
   
   

   3. 12 m/sec.

   
   
   

   4. 15.5 m/sec.

   
   
   

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1. View Hint View Answer Discuss in Forum

   30.6 kmph
   

   	30.06 ×	5		m/sec.
   		18

   
   = 8.5 m/sec

   Correct Option: A

   30.6 kmph
   

   	30.06 ×	5		m/sec.
   		18

   
   = 8.5 m/sec

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338. A man covers	2	of the total journey
     	15

     by train,	9	by bus and the remaining
     	20

     10 km on foot. His total journey (in km) is

1. 1. 15.6

   
   
   

   2. 24

   
   
   

   3. 16.4

   
   
   

   4. 12.8

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let the total journey be of x km, then
   

   2x	+	9x	+ 10 = x
   15		20

   
   

   ⇒  x −	2x	−	9x	= 10
   	15		20

   
   

   ⇒	60x − 8x − 27x	= 10
   	60

   
   

   ⇒	25x	= 10
   	60

   
   

   ⇒ x =	60 × 10	= 24 km
   	25

   Correct Option: B

   Let the total journey be of x km, then
   

   2x	+	9x	+ 10 = x
   15		20

   
   

   ⇒  x −	2x	−	9x	= 10
   	15		20

   
   

   ⇒	60x − 8x − 27x	= 10
   	60

   
   

   ⇒	25x	= 10
   	60

   
   

   ⇒ x =	60 × 10	= 24 km
   	25

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339. You arrive at your school 5 minutes late if you walk with a speed of 4 km/h, but you arrive 10 minutes before the scheduled time if you walk with a speed of 5 km/h. The distance of your school from your house (in km) is

1. 1. 4

   
   
   

   2. 5

   
   
   

   3. 10

   
   
   

   4. 2

   
   
   

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1. View Hint View Answer Discuss in Forum

   If the required distance be = x km, then
   

   x	−	x	=	10 + 5
   4		5		60

   
   

   ⇒	5x − 4x	=	1
   	20		4

   
   

   ⇒	x	=	1
   	20		4

   
   

   ⇒ x =	1	× 20 = 5 km.
   	4

   
   
   Second Method :
   Here, S₁ = 4, t₁ = 5
   S₂ = 5, t₂ = 10
   

   Distance =	(S1 × S2)(t1 + t2)
   	S1 − S2

   
   

   =	(4 × 5)(5 + 10)
   	5 − 4

   
   

   = 20 ×	15	= 5 kms
   	60

   Correct Option: B

   If the required distance be = x km, then
   

   x	−	x	=	10 + 5
   4		5		60

   
   

   ⇒	5x − 4x	=	1
   	20		4

   
   

   ⇒	x	=	1
   	20		4

   
   

   ⇒ x =	1	× 20 = 5 km.
   	4

   
   
   Second Method :
   Here, S₁ = 4, t₁ = 5
   S₂ = 5, t₂ = 10
   

   Distance =	(S1 × S2)(t1 + t2)
   	S1 − S2

   
   

   =	(4 × 5)(5 + 10)
   	5 − 4

   
   

   = 20 ×	15	= 5 kms
   	60

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340. Sound travels at 330 metre per second. The distance (in kilometre) of a thunder cloud when its sound follows the flash after 10 seconds is :

1. 1. 0.33 km.

   
   
   

   2. 3.3 km.

   
   
   

   3. 33 km.

   
   
   

   4. 33.3 km.

   
   
   

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1. View Hint View Answer Discuss in Forum

   Distance = Speed × Time
   = 330 × 10 = 3300 metre
   

   =		3300		km. = 3.3 km.
   		1000

   Correct Option: B

   Distance = Speed × Time
   = 330 × 10 = 3300 metre
   

   =		3300		km. = 3.3 km.
   		1000

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