Question

a metal container open from the top is in the shape of a frustrum of a cone of height with radii of its lower and upper circular ends as 8cm and 20cm respectilvely. find the cost of the milk which can be completely fill the container at the rate of 35RS per litre. also find the area of the metal sheet used

Answer 1

Answer:

Solution :-Radius of the upper end of the container = 20 cmRadius of the lower end of the container = 8 cmContainer is in the shape of frustum.Height of the frustum = 21 cmVolume of the container = 1/3πh[R² + r²+ (R*r)] ⇒ 1/3*22/7*21*[20² + 8² + (20*8)]⇒ 1/3*22/7*21*(400 + 64 + 160)⇒ (462*624)/21⇒ 288288/21= 13728 cu cmAs we know that 1 litre = 1000 cu cmSo, 13728 cu cm = 13728/1000= 13.728 litreRate of milk = Rs. 35 per litreTotal cost = 13.728 × 35= Rs. 480.48