A spherical ball of radius 3 cm is melted and recast into three spherical balls. The radii of two of the balls are 1.5 cm and 2 cm. Find the diameter of the third ball.
Let radius of the third ball be r.
Volume of the larger ball = 
Volume of larger ball = sum of volume of smaller balls
⇒ r3 = 27 – 3.375 – 8
⇒ r = 2.5cm
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