Question

A container, opened from the top and made up of a metal sheet, is in the form of a frustum of a cone of height 16cm with radii of its lower and upper ends as 8cm and 20cm respectively. Find the cost of the milk which can completely fill the container, at the rate of ₹20 per litre. Also find the cost of metal sheet used to make the container, if it cost ₹8 per 100cm2.(Take π = 3.14)

Answer 1

Answer:

Step-by-step explanation:

Height of frustum of a cone = h = 24 cm

Radius of lower end = r = 8 cm

Radius of upper end = R = 20 cm

Volume of frustum of cone  V = (πh) / 3 x (R2 + Rr + r2)

                                     V = (π24) / 3 x (202 + 20x8 + 82)    

                                     V = 176 / 7 x 624

                                     V = 176 x 89.142 cm3

                                     V = 15688.992 cm3

                                    V = 15688.992 cm3 / 1000

                                     V = 15.688992 liter

Cost of milk per liter fill the container = 21 Rs

∴ Total cost of milk  fill the container = 15.688992 x 21 = 329.4688 Rs ≃ 330 rupees