volume of tub = 20 *10*10 = 2000cm^3
2000*1/16 = 2000/16 = 125 cubic cm of ice scream left
volume of sphere = 4/3*3.14*3^2 = 37.68 / 2 = 18.84
volume of cone = 18.84
18.84 = 1/3 *3.14*r^2*h
18.84 = 9.42*h
h = 18.84 / 9.42 = 2.00 inches tall