Two trains are moving in opposite directions with the same speed. If the length of each train is 120 metres and they cross each other in 12 seconds, then what is the speed (in km/hr) of each train?
P and Q undertook to do a work for Rs 7200. P alone could do it in 20 days and Q alone in 12 days. With the assistance of R they finished the work in 5days. What is the share (in Rs) of R?