191. Two trains, 80 metres and 120 metres long, are running at the speed of 25 km/hr and 35 km/hr respectively in the same direction on parallel tracks. How many seconds will they take to pass each other ?

1. 1. 48

   
   
   

   2. 64

   
   
   

   3. 70

   
   
   

   4. 72

   
   
   

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1. View Hint View Answer Discuss in Forum

   Relative speed = 35 – 25 = 10 kmph
   

   =	10 × 5	m/sec.
   	18

   
   Total length = 80 + 120 = 200 metres
   

   ∴   Required time =	Sum of the lengths of trains
   	Relative speed

   
   

   =	200
   	10 × 5
   	18

   
   

   =	200 × 18	= 72 seconds
   	10 × 5

   Correct Option: D

   Relative speed = 35 – 25 = 10 kmph
   

   =	10 × 5	m/sec.
   	18

   
   Total length = 80 + 120 = 200 metres
   

   ∴   Required time =	Sum of the lengths of trains
   	Relative speed

   
   

   =	200
   	10 × 5
   	18

   
   

   =	200 × 18	= 72 seconds
   	10 × 5

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192. In a 100m race, Kamal defeats Bimal by 5 seconds. If the speed of Kamal is 18 Kmph, then the speed of Bimal is

1. 1. 15.4 kmph

   
   
   

   2. 14.5 kmph

   
   
   

   3. 14.4 kmph

   
   
   

   4. 14 kmph

   
   
   

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1. View Hint View Answer Discuss in Forum

   Time taken by Kamal
   

   =	100					= 20 seconds
   	18 ×	5
   		18

   
   ∴   Time taken by Bimal
   = 20 + 5 = 25 seconds
   

   ∴  Bimal’s speed =	100	= 4 m/sec
   	25

   
   

   =	4 × 18	kmph = 14.4 kmph.
   	5

   Correct Option: C

   Time taken by Kamal
   

   =	100					= 20 seconds
   	18 ×	5
   		18

   
   ∴   Time taken by Bimal
   = 20 + 5 = 25 seconds
   

   ∴  Bimal’s speed =	100	= 4 m/sec
   	25

   
   

   =	4 × 18	kmph = 14.4 kmph.
   	5

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193. A and B start at the same time with speed of 40 km/hr and 50 km/hr respectively. If in covering the journey A takes 15 minutes longer than B, the total distance of the journey is :

1. 1. 46 km

   
   
   

   2. 48 km

   
   
   

   3. 50 km

   
   
   

   4. 52 km

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let the distance be x km
   

   Time taken by A =	x	hrs.
   	40

   
   

   Time taken by B =	x	hrs.
   	50

   
   

   Now,	x	−	x	=	15
   	40		50		60

   
   

   5x − 4x	=	15
   200		60

   
   

   ∴  x =	15	× 200 = 50km
   	60

   
   
   Second Method :
   

   Distance =	Product of speed	× Diff. in time
   	Diff. of speed

   
   

   =	40 × 50	×	15	= 50km
   	50 − 40		60

   Correct Option: C

   Let the distance be x km
   

   Time taken by A =	x	hrs.
   	40

   
   

   Time taken by B =	x	hrs.
   	50

   
   

   Now,	x	−	x	=	15
   	40		50		60

   
   

   5x − 4x	=	15
   200		60

   
   

   ∴  x =	15	× 200 = 50km
   	60

   
   
   Second Method :
   

   Distance =	Product of speed	× Diff. in time
   	Diff. of speed

   
   

   =	40 × 50	×	15	= 50km
   	50 − 40		60

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194. I walk a certain distance and ride back taking a total time of 37 minutes. I could walk both ways in 55 minutes. How long would it take me to ride both ways?

1. 1. 9.5 minutes

   
   
   

   2. 19 minutes

   
   
   

   3. 18 minutes

   
   
   

   4. 20 minutes

   
   
   

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1. View Hint View Answer Discuss in Forum

   Two ways walking time = 55 min    ...(i)
   One way walking + One way riding time = 37 min.     ....(ii)
   By 2 × (ii) – (i),
   2 ways riding time
   = 2×37–55 = 19 minutes

   Correct Option: B

   Two ways walking time = 55 min    ...(i)
   One way walking + One way riding time = 37 min.     ....(ii)
   By 2 × (ii) – (i),
   2 ways riding time
   = 2×37–55 = 19 minutes

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195. Rubi goes to a multiplex at the speed of 3 km/hr to see a movie and reaches 5 minutes late. If she travels at the speed of 4 km/hr she reaches 5 minutes early. Then the distance of the multiplex from her starting point is

1. 1. 2 km.

   
   
   

   2. 5 km.

   
   
   

   3. 2 metre

   
   
   

   4. 5 metre

   
   
   

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1. View Hint View Answer Discuss in Forum

   Distance between starting
   point and multiplex = x metre
   

   Time =	Distance
   	Speed

   
   According to the question,
   

   x	−	x	=	5 + 5	⇒	4x − 3x	=	1
   3		4		60		12		6

   
   

   ⇒	x	=	1	⇒ x =	12	= 2 km.
   	12		6		6

   Correct Option: A

   Distance between starting
   point and multiplex = x metre
   

   Time =	Distance
   	Speed

   
   According to the question,
   

   x	−	x	=	5 + 5	⇒	4x − 3x	=	1
   3		4		60		12		6

   
   

   ⇒	x	=	1	⇒ x =	12	= 2 km.
   	12		6		6

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