The spherical ball of lead 3 cm in diameter is melted and recast into 3 spherical balls. The diameters of two of these are 1 ½ cm and 2 cm respectively. The diameter of third ball is?

A. 2.66 cm
B. 2.5 cm
C. 3 cm
D. 3.5 cm

4/3 π * 3 * 3 * 3 = 4/3 π[(3/2)³ + 2³ + r³]

r = 1.25

d = 2.5