A metallic solid spherical ball of radius 3 cm is melted recast into three spherical balls. The radii of two of these balls are 2 cm and 1.5 cm. What is the surface area (in cm2) of the third ball?

Answer: Option C

$$\frac{4}{3}$$π × 3 × 3 × 3 = $$\frac{4}{3}$$π × 2³ + $$\frac{4}{3}$$π × (1.5)³ + $$\frac{4}{3}$$π × r³
27 = 8 + 3.375 + r³
15.625 = r³
r = 2.5 cm
∴ The surface area of the third ball = 4π × 2.5 × 2.5 = 25π cm²