Three spherical balls of radii 1 cm, 2 cm and 3 cm are melted to form a single spherical ball. In the process, the loss of material is 25%. The radius of the new ball is - Zigya
Advertisement

Three spherical balls of radii 1 cm, 2 cm and 3 cm are melted to form a single spherical ball. In the process, the loss of material is 25%. The radius of the new ball is

  • 6 cm

  • 5 cm

  • 3 cm

  • 3 cm


C.

3 cm

Material lost  = 25% = 1 fourth
Remaining material = open parentheses 1 minus 1 fourth close parentheses space equals space 3 over 4
Volume of the new ball
     equals space 3 over 4 space cross times space 4 over 3 straight pi open parentheses straight r subscript 1 cubed space plus space straight r subscript 2 cubed space plus space straight r subscript 3 cubed close parentheses
space equals space straight pi left parenthesis 1 cubed space plus space 2 cubed space plus space 3 cubed right parenthesis
space equals space straight pi left parenthesis 1 space plus space 8 plus space 27 right parenthesis
space equals space 36 space straight pi space cm cubed

therefore space space space space space 4 over 3 πr cubed space equals space 36 straight pi
rightwards double arrow space space space straight r cubed space equals space fraction numerator 36 space cross times space 3 over denominator 4 end fraction space equals space 27
space space space therefore space space space straight r space equals space cube root of 27 space equals space 3 space cm

 
 

450 Views

Advertisement

Mensuration - Volume and Surface Areas

Hope you found this question and answer to be good. Find many more questions on Mensuration - Volume and Surface Areas with answers for your assignments and practice.

QA01

Browse through more topics from QA01 for questions and snapshot.