Nov 19, 2010

12. Find the speed of the 2nd train.

A train 108m long moving at a speed of 50km/hr crosses a train 112m long coming from opposite direction in 6sec.The speed of the 2nd train is??


Answer:
82 km/hr
Explanation:
Let the speed of the second train be x km/hr.
Relative speed= (x + 50) km/hr

=[(x + 50) x5]m/sec
18

=[250 + 5x]m/sec.
18

Distance covered = (108 + 112) = 220 m.
Therefore220= 6
(250 + 5x(
18
=> 250 + 5x = 660
=> x = 82 km/hr.

11. Find the direction.

If South-East becomes North, North-East becomes West and so on. What will West become?

Answer: 
South - East
Explanation:
It is clear from the diagrams that new name of West will become South-East.