ABC26GN4933 · Volume and Surface Area

Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:

A cylindrical tube open at both ends is made of metal. The internal diameter of the tube is 11.2 m and its length is 21 cm. The metal everywhere is 0.4 cm thick. The volume of the metal is

(a)$280.52 \mathrm{cm}^{3}$

(b)$306.24 \mathrm{cm}^{3}$

(c)$310 \mathrm{cm}^{3}$

(d)$316 \mathrm{cm}^{3}$

Answer

Answer (as printed): B

Explanation

Internal radius $=\left(\frac{11.2}{2}\right) \mathrm{cm}=5.6 \mathrm{cm}$, External radius $=(5.6+0.4) \mathrm{cm}=6 \mathrm{cm}$. Volume of metal $$\begin{aligned} =\left\{\frac{22}{7} \times\left[(6)^{2}-(5.6)^{2}\right] \times 21\right\} \mathrm{cm}^{3} & =(66 \times 11.6 \times 0.4) \mathrm{cm}^{3} \\ & =306.24 \mathrm{cm}^{3} . \end{aligned}$$

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