Question

By melting an iron sphere of radius 6 cm, 3 small spheres are made whose radius are in the ratio 3: 4: 5. The radius of smallest sphere is

• A. 8
• B. 3
• C. 4
• D. 6

Answer 1

Answer:

B. 3

Volumes of the small spheres =(4/3)π(3x)³, (4/3)π(4x)³, (4/3)π(5x)³ Total volume of small spheres =(4/3)π(3x)³+ (4/3)π(4x)³+ (4/3)π(5x)³ =(4/3)π(27x³+64x³+125x³) =(4/3)π × 216x³ Volume of largest spheres = Total volume of small spheres (4/3)π × 216=(4/3)π × 216x³ x³=1 x=1 Radius of smaller sphere = 3x=3x1=3