# The outer radius and the inner radius of a 30 cm long cylindrical gold pipe are 14 cm and 7 cm respectively. It is filled with bronze. The densities o

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The outer radius and the inner radius of a 30 cm long cylindrical gold pipe are 14 cm and 7 cm respectively. It is filled with bronze. The densities of gold and bronze are 20gm/cm^(3) and 30gm/cm^(3) respectively. Find the weight of the cylinder formed. (in gm)
A. 66150pi
B. 99225pi
C. 132300pi
D. 198450pi

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Volume of the pipe =pi (14^(2)-7^(2))(30)cm^(3)
 :. " Volume of the gold "=pi (14^(2)-7^(2))(30)cm^(3)
Volume of the bronze in the pipe =pi (7)^(2)(30) cm^(3)
Weight of the pipe (in gms) = Weight of gold in it (in gm) + Weight of bronze in it (in gm)
=[pi (14^(2)-7^(2))(30)][20]+[pi(7)^(2)(30)][30]
=30pi[(196-49)(20)+(49)(30)]
=30pi [2940 + 1470]=132300 pi gm.