Problem: a cylindrical container of radius 6 cm and height 15 cm is filled with ice - cream . the whole icecream has to be distributed to 10 children in equal cones with hemispherical tops . if the height of the conical portion is four times the radius of its base , find the radius of the ice - cream cone . 
Options: ['a ) 1', 'b ) 2', 'c ) 3', 'd ) 4', 'e ) 5']
c