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Q:

A and B runs around a circular track. A beats B by one round or 10 minutes. In this race, they had completed 4 rounds. If the race was only of one round, find the A's time over the course:

A) 8 min B) 7.5 min
C) 12.5 min D) 12 min

Answer:   B) 7.5 min

Explanation:

B runs around the track in 10 min.

i.e ,    Speed of B = 10 min per round

 A beats B by 1 round

Time taken  by A to complete 4 rounds 

            = Time taken by B to complete 3 rounds 

            = 30 min

 A's speed = 30/4 min per round

                        = 7.5 min per round

Hence, if the race is only of one round A's time over the course = 7 min 30 sec

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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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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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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