Question

A cylindrical vessel without lid has to be painted on its both side if the radius of the base is 70 cm and its height is 1.4 M calculate the cost of tin coating @ rupees 3.50 per thousand CM sqare

Answer 1

Given that,

the cylindrical vessel is without lid which means that we will need to take out the Curved Surface Area alongwith the are of its circular base.

Radius of the cylinder's base = 70 cm

Height of the vessel = 1.4 m = 140 cm

So, the required Surface area of the vessel = Curved Surface Area of the cylinder + Surface area of the circular base

= 2πrh + πr^2

= πr (2h + r)

$= \frac{22}{7} (2 \times 140 + 70) \\ \\ = \frac{22}{7} (280 + 70) \\ \\ = \frac{22}{7} (350) \\ \\ = 22 \times 50 \\ \\ = 1100 \: {cm}^{2}$

Thus, the area to be painted is 1100 sq. Cms.

Given that, the cost of tim coating is at the rate of ₹3.50 per thousand sq. Cms.

So, the cost of tin coating per sq. Cms will be 3.50/1000.

The total cost = area of the vessel × cost per sq. Cm.

$= 1100 \times \frac{3.50}{1000} \\ \\ = rs. \: 3.85$

Thus, the cost of tin coating will be ₹ 3.85.