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Q:

A man walking at the rate of 5 km/hr crosses a bridge in 15 minutes. The length of the bridge (in metres) is

A) 600 B) 750
C) 1000 D) 1250

Answer:   D) 1250

Explanation:

speed    = (5x5/18)m/sec
             = 25/18 m/sec.


Distance covered in 15 minutes    = (25/18 x 15 x 60)m
                                                 = 1250 m.

Q:

A man rows his boat 60 km downstream and 30 km upstream taking 3 hrs each time. Find the speed of the stream ?

A) 5 kmph B) 10 kmph
C) 15 kmph D) 45 kmph
 
Answer & Explanation Answer: A) 5 kmph

Explanation:

Speed of the boat downstream   = 

Speed of the boat upstream 

 The speed of the stream = .

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6 121
Q:

Mr. Karthik drives to work at an average speed of 48 km/hr. Time taken to cover the first 60% of the distance is 20 minutes more than the time taken to cover the remaining distance. Then how far is his office ?

A) 40 km B) 50 km
C) 70 km D) 80 km
 
Answer & Explanation Answer: D) 80 km

Explanation:

Let the total distance be 'x' km.
Time taken to cover remaining 40% of x distance is   
But given time taken to cover first 60% of x distance is   
  

  x=80 km.

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6 51
Q:

Two bike riders ride in opposite directions around a circular track, starting at the same time from the same point. Biker A rides at a speed of 16 kmph and biker B rides at a speed of 14 kmph. If the track has a diameter of 40 km, after how much time (in hours) will the two bikers meet?

A) 6.52 B) 8.14
C) 4.18 D) 5.02
 
Answer & Explanation Answer: C) 4.18

Explanation:

Distance to be covered =  = 40  km

Relative speed of bikers = 16 + 14 = 30 kmph.

Now,  =   = 4.18 hrs.

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7 137
Q:

A man is riding a bike with front and back wheel circumference of 40 inches and 70 inches respectively. If the man rides the bike on a straight road without slippage, how many inches will the man have travelled when the front wheel has made 15 revolutions more than the back wheel?

A) 1100 B) 1300
C) 1400 D) 1200
 
Answer & Explanation Answer: C) 1400

Explanation:

Given the ratio of the circumference of front wheel  is 40 inches and back wheel is 70 inches 

Distance covered = Circumference of the wheel × No. of Revolutions made by the wheel

If n is the number of revolutions made by back wheel, the number of revolutions made by front wheel is n+15

Distance covered by both the wheels is the same

40*(n+3)=70n

n=20

                Front wheel    :      Back Wheel

Circumference       40      :      70

Revolutions           35      :      20

Distance covered             40×35 = 70×20 = 1400 inches.

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7 67
Q:

Two trains 85 m and 75 m long are running in same direction with speeds of 62 km/hr and 44 km/hr respectively. In what time will the first train cross the second train ?

A) 22 sec B) 32 sec
C) 42 sec D) 52 sec
 
Answer & Explanation Answer: B) 32 sec

Explanation:

Given that,

1st train speed = 62 km/hr 

2nd train speed  = 44 km/hr

Hence the relative speed of two trains is 62-44 = 18 km/hr   m/s = 5 m/s.

There fore, the first train crosses the second train i.e (85+75)mts of distance with a speed of 5m/s in,

 

time   = 32 sec.

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