The distance of the college and home of Rajeev is 80km. One day he was late by 1 hour than the normal time to leave for the college, so he increased his speed by 4km/h and thus he reached to college at the normal time. What is the changed (or increased) speed of Rajeev?

Correct Answer: 150m

Explanation:

Let the length of the train e x meter, and let the speed of train be y km/h, then

x = y + 3 × 5 18 × 36   --------(1)   and   

x = y + 6 × 5 18 × 30  ---------(2)

  

From eq (1) and (2), we get      

y = 12 km/h

Therefore,   x = ( y + 3 ) × 5 18 × 36   =>  x= 150 m

Correct Answer: 172 m

Explanation:

Ratio of speeds of A:B = 1000:900 = 100:90 Ratio of speeds of B:C = 1000:920 = 100:92 Therefore, when A moves 1000m, B moves 900 m and when B moves 900m, C moves 828m Since, C moves 8 % less than B at the same time. Thus, C is the worst performer and A will win by him by 172 m

Correct Answer: 8:56 am

Explanation:

Time taken by Akash = 4 h

Time taken by Prakash = 3.5 h

For your convenience take the product of times taken by both as a distance.

Then  the distance = 14km

Since, Akash covers half of the distance  in 2 hours(i.e at 8 am)

Now, the rest half (i.e 7 km) will be coverd by both prakash and akash

Time taken by them = 7/7.5 = 56 min

Thus , they will cross each other at  8 : 56am.

Correct Answer: 11 a.m

Explanation:

Suppose they meet x hrs after 8 a.m

then,

[Distance moved by first in x hrs] + [Distance moved by second in (x-1) hrs] = 330.

Therefore, 60x + 75(x-1) = 330.

 => x=3.

So,they meet at (8+3) i.e, 11a.m.

Correct Answer: 71.11 km/hr

Explanation:

Total time taken    = (160/64 + 160/8)hrs
                           = 9/2 hrs.

Average speed    = (320 x 2/9) km.hr
                         = 71.11 km/hr.

Correct Answer: 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 

        L R - A = 36 ---------- (i) 

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

 

= (3600 - 24) = 3576 s                            

Correct Answer: 75

Explanation:

The hour hand moves from pointing to 12 to pointing to half way between 2 and 3. The angle covered between each hour marking on the clock is 360/12 = 30. Since the hand has covered 2.5 of these divisions the angle moved through is 75.

Correct Answer: 87.5 km/hr

Explanation:

Let the speeds of two trains be 7X and 8X km/hr.

8x = 400/4

=> x= 12.5 km/hrX=4004=>X=12.5Km/hr

So speed of first train is 12.5*7 = 87.5 km/hr

Correct Answer: 8

Explanation:

Amy can travel clockwise or anticlockwise on the diagram.

Clockwise, she has no choice of route from A to B, a choice of one out of two routes from B to C, and a choice of one out of two routes from C back to A. This gives four possible routes.

Similarly, anticlockwise she has four different routes.

Total routes = 8

Correct Answer: 60 km/hr

Explanation:

We are having time and speed given, so first we will calculate the distance. Then we can get new speed for given time and distance.
Lets solve it.

Time = 50/60 hr = 5/6 hr
Speed = 48 mph
Distance = S*T = 48 * 5/6 = 40 km

New time will be 40 minutes so,
Time = 40/60 hr = 2/3 hr
Now we know,
Speed = Distance/Time
New speed = 40*3/2 kmph = 60kmph