A cylindrical container is to be made of tin sheet. The height of the container is 1 m and its diameter is 70 cm. If the container is open at the top and the tin sheet costs 300 per m², find the cost of the tin for making the container.

Since, container is open at the top hence total surface area of container (S) = curved surface area + area of base.

Radius of container = $\dfrac{70}{2}$ = 35 cm = 0.35 m.

$\Rightarrow S = 2πrh + πr^2 \\[1em] = 2 \times \dfrac{22}{7} \times 0.35 \times 1 + \dfrac{22}{7} \times 0.35 \times 0.35 \\[1em] = 2 \times 22 \times 0.5 + 22 \times 0.5 \times 0.35 \\[1em] = 22 + 3.85 \\[1em] = 25.85 \text{ m}^2$

Cost of 1 m² sheet = ₹ 300.

Total cost = ₹ 300 × 25.85 = ₹ 775.50

Hence, the cost of tin for making the container is ₹ 775.50