Question

An open container made up of a metal sheet is in the form of a frustum of a cone of height 8 cm with radii of its lower and upper ends as 4 cm and 10 cm respectively. Find the cost of oil which can completely fill the container at the rate of rs. 50 per litre. Also, find the cost of metal used, if it costs rs. 5 per 100 cm2.

Answer 1

Volume of frustum =

$\frac{1}{3} \pi h( {r1}^{2} + {r2}^{2} + r1 \times r2)$
If u substitute all the values

you will get the volume as

2614.2 cm^3

Quantity = 2614.2 ml = 2.6 litres

Cost = 2.6 × 50 = 120

Metal sheet used = CSA

$\pi( r1 + r2)l$

L = 10 cm

If you apply in the formula

CSA = 440 cm^2

cost per 100 cm^2 = 5

Cost per cm^2 = 5 / 100 = 1/ 20

Cost of 440 cm^2 = 440/20

Cost = 22

Answer 2

ANSWER:-

Hope it helps you