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Q:

Two horses start trotting towards each other, one from A to B and another from B to A. They cross each other after one hour and the first horse reaches B, 5/6 hour before the second horse reaches A. If the distance between A and B is 50 km. what is the speed of the slower horse?

A) 30 km/h B) 15 km/h
C) 25 km/h D) 20 km/h

Answer:   D) 20 km/h



Explanation:

If the speed of the faster horse be \inline f_{s} and that of slower horse be \inline s_{s} then

             \inline f_{s}+s_{s}=\frac{50}{1}=50

and       \inline \frac{50}{s_{s}}-\frac{50}{f_{s}}=\frac{5}{6}

Now, you can go through options.

The speed of slower  horse is 20km/h

Since,   20+30=50

and      \inline \frac{50}{20}-\frac{50}{30}=\frac{5}{6}

Q:

Joel travels the first 3 hours of his journey at 60 mph speed and the remaining 5 hours at 24 mph speed. What is the average speed of Joel's travel in kmph ?

A) 38 kmph B) 40 kmph
C) 60 kmph D) 54 kmph
 
Answer & Explanation Answer: C) 60 kmph

Explanation:

Average speed = Total distance / Total time.

Total distance traveled by Joel = Distance covered in the first 3 hours + Distance covered in the next 5 hours.

Distance covered in the first 3 hours = 3 x 60 = 180 miles
Distance covered in the next 5 hours = 5 x 24 = 120 miles

Therefore, total distance traveled = 180 + 120 = 300 miles.

Total time taken = 3 + 5 = 8 hours.

Average speed = 300/8 = 37.5 mph.

we know that 1 mile = 1.6 kms

=> 37.5 miles = 37.5 x 1.6 = 60 kms

Average speed in Kmph = 60 kmph.

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2 72
Q:

Two persons start running simultaneously around a circular track of length 600 m from the same point at speeds of 25 kmph and 35 kmph. When will they meet for the first time any where on the track  ?

A) 54 sec B) 36 sec
C) 72 sec D) 11 sec
 
Answer & Explanation Answer: B) 36 sec

Explanation:

Time taken to meet the first time = length of track/relative speed

Given the length of the track is 600 m

The relative speed = 25 + 35 = 60 kmph = 60 x 5/18 m

Therefore Time =   = 600/60 x (18/5) = 36 sec.

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2 61
Q:

A boy can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is ?

A) 1.8 kmph B) 2 kmph
C) 2.2 kmph D) 1.5 kmph
 
Answer & Explanation Answer: D) 1.5 kmph

Explanation:

Speed of Boy is B = 4.5 kmph

Let the speed of the stream is S = x kmph

Then speed in Down Stream = 4.5 + x

speed in Up Stream = 4.5 - x

As the distance is same,

=> 4.5 + x = (4.5 - x)2

=> 4.5 + x = 9 -2x

3x = 4.5

x = 1.5 kmph

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4 92
Q:

A man can row 6 kmph in still water. When the river is running at 1.2 kmph, it takes him 1 hour to row to a place and back. What is the total distance traveled by the man ?

A) 4.58 kms B) 6.35 kms
C) 5.76 kms D) 5.24 kms
 
Answer & Explanation Answer: C) 5.76 kms

Explanation:

Speed in still water = 6 kmph

Stream speed = 1.2 kmph

Down stream  = 7.2 kmph

Up Stream = 4.8 kmph

x/7.2 + x/4.8 = 1

x = 2.88

Total Distance  = 2.88 x 2 = 5.76 kms

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2 66
Q:

A person travels from K to L a speed of 50 km/hr and returns by increasing his speed by 50%. What is his average speed for both the trips ?

A) 55 kmph B) 58 kmph
C) 60 kmph D) 66 kmph
 
Answer & Explanation Answer: C) 60 kmph

Explanation:

Speed on return trip = 150% of 50 = 75 km/hr.

Average speed = (2 x 50 x 75)/(50 + 75) = 60 km/hr.

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