Lessons

General Aptitude
8.1 Volume and Surface Area - General Questions

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Q.

A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:

View Answer

Correct choice: B

Explanation:

External radius = 4 cm,

Internal radius = 3 cm.

Volume of iron
= 22 x [(4)2 - (3)2] x 21 cm3
7
 
= 22/ x 7 x 1 x 21 cm3
7
  = 462 cm3.

∴ Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.

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