An inverted conical shaped vessel is filled with water to its brim. The height of the vessel is 8 cm and radius of the open end is 5 cm . When a few solid spherical metallic balls each of radius 1⁄2 cm are dropped in the vessel , 25% water is overflowed. The number of balls is:
Present age of Amit is twice of Baman’s present age. After 5 years Baman’s age will be 4 times of the Chetan’s present age. If Chetan celebrated his sixth birthday 7 years ago, then what will be the present age (in years) of Amit?
Pipe A can empty a filled tank in 28 hours while Pipe B can fill the same tank, when empty in 35 hrs. If alternatively Pipes A and B are turned on for an hour each time, starting when the tank is full, how long will it take to empty the tank?