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Q:

A train with 120 wagons crosses Arun who is going in the same direction, in 36 seconds. It travels for half an hour from the time it starts overtaking the Arun ( he is riding on the horse) before it starts overtaking the Sriram( who is also riding on his horse) coming from the opposite direction in 24 seconds. In how much time (in seconds) after the train has crossed the Sriram do the Arun meets to Sriram?

A) 3560 sec B) 3600 sec
C) 3576 sec D) can't be determined

Answer:   C) 3576 sec

Explanation:

Let the length of the train be L metres and speeds of the train Arun and Sriram be R, A and S respectively, then 

         ---------- (i)

and  ---------(ii)

From eq.(i) and (ii)

             3(R - A ) = 2 (R + K)

    R = 3A + 2K

In 30 minutes (i.e 1800 seconds), the train covers 1800R (distance) but the Arun also covers 1800 A (distance) in the same time. Therefore distance between Arun and Sriram, when the train has just crossed Sriram

              = 1800 ( R - A) - 24 ( A + K)

 Time required =

= (3600 - 24) = 3576 s                            

Q:

K is 50% faster than L. If L starts at 9 A.M. and K starts at 10 A.M. L travels at a speed of 50 km/hr. If L and K are 300 kms apart, The time when they meet when they travel in opposite direction is ?

A) 12 pm B) 1 pm
C) 11 am D) 11:30 am
 
Answer & Explanation Answer: A) 12 pm

Explanation:

let 't' be the time after which they met since L starts.

Given K is 50% faster than L

50 t + 1.5*50(t-1) = 300

50 t +75 t = 300 + 75

t = 375 / 125 = 3 hrs past the time that L starts

So they meet at (9 + 3)hrs = 12:00 noon.

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3 51
Q:

A goods truck travels from a place at a certain time and at fixed speed. After 6hrs another truck leaves the same place and move in same direction of uniform speed of 90kmph. The truck catches up the goods truck in 4hrs. Find the speed of the goods truck ?

A) 36 kmph B) 32 kmph
C) 28 kmph D) 34 kmph
 
Answer & Explanation Answer: A) 36 kmph

Explanation:

Let the speed of goods truck be 'p' kmph
Distance covered by goods truck in 10hrs (4+6) = Distance covered by other truck in 4 hrs.
10p = 4 x 90
p = 36kmph.
Therefore, the speed of the goods truck is p = 36 kmph.

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3 15
Q:

A man covers a distance of 1200 km in 70 days resting 9 hours a day, if he rests 10 hours a day and walks with speed 1½ times of the previous in how many days will he cover 840 km ?

A) 39 days B) 37 days
C) 35 days D) 33 days
 
Answer & Explanation Answer: C) 35 days

Explanation:

Distance d = 1200km
let S be the speed

he walks 15 hours a day(i.e 24 - 9)
so totally he walks for 70 x 15 = 1050hrs.

S = 1200/1050 => 120/105 = 24/21 => 8/7kmph


given 1 1/2 of previous speed
so 3/2 * 8/7= 24/14 = 12/7

New speed = 12/7kmph

Now he rests 10 hrs a day that means he walks 14 hrs a day.

time = 840 x 7 /12 => 490 hrs
=> 490/14 = 35 days

So he will take 35 days to cover 840 km.

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4 38
Q:

You drive to the store at 20 kmph and return by the same route at 30 kmph. Discounting the time spent at the store, what was your average speed ?

A) 25 kmph B) 24 kmph
C) 26 kmph D) 22 kmph
 
Answer & Explanation Answer: B) 24 kmph

Explanation:

Average speed=total distance/total time
Let distance to store be  K
then, total time =(K/20)+(K/30)=K/12
and, total time =(2K)
so average speed= 2K / (K/12) = 24kmph.

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2 18
Q:

A man reaches his office 20 min late, if he walks from his home at 3 km per hour and reaches 30 min early if he walks 4 km per hour. How far is his office from his house ?

A) 20 km B) 16 km
C) 14 km D) 10 km
 
Answer & Explanation Answer: D) 10 km

Explanation:

Let distance = x km.
Time taken at 3 kmph : dist/speed = x/3 = 20 min late.
time taken at 4 kmph : x/4 = 30 min earlier
difference between time taken : 30-(-20) = 50 mins = 50/60 hours.
x/3- x/4 = 50/60
x/12 = 5/6
x = 10 km.

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