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Q:

Shahrukh starts from Barabanki to Fatehpur , 1 hour after Ajay starts. Shahrukh meets Kajol 1.5 hours after Shahrukh starts. If the speed of Shahrukh is at least 20km/h faster than the speed of Kajol.

What is the minimum speed of Shahrukh to overtake Ajay, before he meets Kajol?

A) 30 B) 40
C) 60 D) None of these

Answer:   D) None of these

Explanation:

Let t be the time after Kajol starts, when she meets Ajay, then 

              \inline t=\frac{300}{(x+y)}

This should be less than 2.5 or (x+y)>120

Since       y= \inline \frac{3x}{2}     \inline \Rightarrow y>72

This (y>72) is greater than 67.5 km/h and hence Shahrukh will always overtake Ajay before he meets Kajol.

Q:

Two motor bikes cover the same distance at the speed of 60 and 64 kmps respectively. Find the distance traveled by them if the slower bike takes 1 hour more than the faster bike ?

A) 1102 km B) 1060 km
C) 960 km D) 1250 km
 
Answer & Explanation Answer: C) 960 km

Explanation:

60(x + 1) = 64x

X = 15

60 x 16 = 960 km

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Q:

A man whose speed is 4.5 kmph in still water rows to a certain upstream point and back to the starting point in a river which flows at 1.5 kmph, find his average speed for the total journey ?

A) 5 kmph B) 7 kmph
C) 3 kmph D) 4 kmph
 
Answer & Explanation Answer: D) 4 kmph

Explanation:

Speed of Man = 4.5 kmph
Speed of stream = 1.5 kmph
Speed in DownStream = 6 kmph
Speed in UpStream = 3 kmph
Average Speed = (2 x 6 x 3)/9 = 4 kmph.

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1 26
Q:

The current of a stream at 1 kmph. A motor boat goes 35 km upstream and back to the starting point in 12 hours. The speed of the motor boat in still water is ?

A) 8 kmph B) 6 kmph
C) 7.5 kmph D) 5.5 kmph
 
Answer & Explanation Answer: B) 6 kmph

Explanation:

Speed of the stream = 1
Motor boat speed in still water be = x kmph
Down Stream = x + 1 kmph
Up Stream = x - 1 kmph
[35/(x + 1)] + [35/(x - 1)] = 12
x = 6 kmph

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1 52
Q:

A Bus is running at 9/10 of its own speed reached a place in 22 hours. How much time could be saved if the bus would run at its own speed ?

A) 1.5 hrs B) 1.7 hrs
C) 2.2 hrs D) 3.5 hrs
 
Answer & Explanation Answer: C) 2.2 hrs

Explanation:

Let the original Speed be "s" kmph
And the usual time be "t" hrs
Given that if the bus is running at 9s/10 kmph the time is 22 hrs
=> [9s/10] x 22 = t x s
=> 99/5 = t
=> t = 19.8 hrs

 

Hence, if bus runs at its own speed, the time saved = 22 - 19.8 = 2.2 hrs.

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Q:

How many seconds will a 800 meter long train moving with a speed of 63 km/hr take to cross a man walking with a speed of 3 km/hr in the direction of the train ?

A) 48 B) 52
C) 38 D) 42
 
Answer & Explanation Answer: A) 48

Explanation:

Here distance d = 800 mts
speed s = 63 - 3 = 60 kmph = 60 x 5/18 m/s
time t = = 48 sec.

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