Two trains are running in opposite directions with the same speed. If the length of each train is 486 metres and they cross each other in 27 seconds, then what is the speed (in km/hr) of each train?
A rectangular swimming pool of length 30 m and breadth 15 m has a uniformly sloping floor. It is 1 m in depth on one end of its length and 2 m at the other. How much water is needed to completely fill this pool?