Raghu's tanker can fill a cistern in 4 hours. After half the cistern is filled, three more similar tankers are opened. What is the total time taken to fillthe cistern completely?
Pihu and Aayu are running on a circular track of diameter 28m. Speed of Pihu is 48 m/s and that of Aayu is 40 m/s. They start from the same point at the same time in the same direction. When will they meet again for the first time?