A hemispherical tank of radius 1 m is full of water. A pipe connected to it empties it at the rate of 7 litres per second. How much time will it take to empty the tank?

Radius of the hemispherical tank = 1 m
                                                   = m ∴ Volume of water in the tank = π r³
                                            = × × × ×
                                            = cu. m
                                            = cu. cm
                                            = × litres
Water emptied per second = 7 litres ∴ Time required to empty the tank = × ×
                                                  = 1604.17 seconds
                                                  =
                                                  = 26.74 minutes