Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:
A closed metallic cylindrical box is 1.25 m high and its base radius is 35 cm. If the sheet metal costs ₹ 80 per $\mathrm{m}^{2}$, the cost of the material used in the box is
(a)₹ 281.60
(b)₹ 290
(c)₹ 340.50
(d)₹ 500
Answer
Answer (as printed): A
Explanation
Total surface area $$\begin{aligned} & =2 \pi r(h+r)=\left[2 \times \frac{22}{7} \times \frac{35}{100} \times(1.25+0.35)\right] \mathrm{m}^{2} \\ & =\left(2 \times \frac{22}{7} \times \frac{35}{100} \times \frac{16}{10}\right) \mathrm{m}^{2}=3.52 \mathrm{m}^{2} \end{aligned}$$ ∴ Cost of the material $=₹(3.52 \times 80)=₹ 281.60$.