Twelve solid hemispheres of the same size are melted and recast to in a cylinder of diameter 7 cm and height 28 cm. What is the radius of the hemispheres?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 3.5 cm
| Understanding | Application |
| Tricks |
⇒The volume of the cylinder = 12 × solid hemisphere ⇒ πr2h = 12 × 2/3 × πr3 ⇒ 7/2 × 7/2 × 28 = 12 × 2/3 × r3 ⇒ 7 × 7 × 7 = 4 × 2 × r3 |
| Hence |
R = 7/2 = 3.5 cm |