In a row, 60 students were standing at a distance 1 meter behind from other and were moving forward with a speed of 3m/s. The last student in a row wanted to convey a message to the 1st student, but he did not want to disturb other. He ran towards the 1st student conveyed the message and returned back to his place. In total, he covered 240 meters. Find the running speed of the student.
A cistern has two pipes. One can fill it in 8 hours, and the other can empty it in 5 hours. In how many hours will the cistern be emptied if both the pipes are opened together when of the cistern is already filled with water?
