Solution:

I am DAVID.

At the core I have 5
If we talk in roman numeric system, 5 = V

Similarly, 500 stands in the beginning and end
500 = D

I also include the first letter i.e. A and the first number i.e. I (in roman numeric system)

All of them combine to form DAVID.

Solution:

XIX is the answer which refers to nineteen in roman numeric system. On taking out one i.e. I, we will get XX that is equal to twenty.

Solution:

99 matches.

The number of matches will always sum up to one less than the number of players in a knock out tournament. You may calculate it in any manner. Thus 99 matches were played.

Solution:

0! or cos(0)

Solution:

245 minutes

It will take 49 cuts not 50.
so 49*5 => 245 minutes

Solution:

24miles/hr (not 25miles/hr which might be guessed by many)

D : distance traveled
T1 : time of going to office
T2 : time of returning back
Y : Average Speed

D = 20 * T1
T1 = D/20

D = 30 * T2
T2 = D/30


2D = Y(T2 + T1)
2D = Y(D/20 + D/30)
2D = Y(3D/60 + 2D/60)
2D = Y(5D/60)
Y = 120D/5D

=> Y = 24

Solution:

303 , 303 , 303 , 303 , 303

Solution:

0(zero) off course.

Solution:

The answer is simple. The trains will be at same distance from Point P when they meet speaking on approximation. However, the train A will be closer to the point P by its own length if we are not taking meeting of train as perfectly overlapping.

Solution:

He will hang clock number 315 at 7:30pm. The person has been hanging the clock number which corresponds with the angle between the hour hand and the minute hand of the clock at that time.