Question
A cylindrical pipe has an external radius of 8 cm and an internal radius of 7 cm. If its length is 20 cm, what is the volume of material used in the pipe? (Use \(\pi = 3.14\))
This question was previously asked in
RRB NTPC 2025 Under Graduate CBT 1 Question Paper PDF (20-Jun-2026) (Shift 3)
The correct answer is
942 cubic cm
Volume of the material of a hollow cylinder = \(\pi(R^{2}-r^{2})h\), where R is external and r is internal radius.
Here R = 8 cm, r = 7 cm, h = 20 cm.
\(R^{2}-r^{2} = 64 - 49 = 15\) cm2.
Volume = \(3.14\times 15\times 20 = 942\) cm3.
Hence, the volume of material used in the pipe is 942 cubic cm.
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