Mango juice is stored to the brim in a cylindrical container for a party. The guests are to be offered the juice in cylindrical glasses having the same radius and height. But instead, the guests are served the juice in hemispherical bowls having a radius equal to that of the cylindrical glasses. If 60 guests drink the juice and 60 % of the cylindrical container becomes empty, no. of guests for which juice was meant for initially are :