Question

A bucket made of aluminium sheet is of height 20 cm and its upper and lower ends are of radius 25 cm and 10 cm respectively. Find the cost of making the bucket if the aluminium sheet costs Rs. 70 per 100 cm².(use π=3.14)

Answer 1

cost of the bucket = Rs. 877.36

Step-by-step explanation:

Bottom radius r = 10/2 = 5cm

Top radius R = 15/2 = 12.5cm

Height of bucket h = 20 cm

Slant height of frustum l = root of (h² + (R-r)²) = root (20² + (12.5-5)²)

   = root (400 + 56.25)  

   = 21.36 cm

Curved Surface area of bucket = π(R+r)l = 22/7 * 17.5 * 21.36 = 1174.8 sq.cm.

Area of base = πr² = 22/7 * 5 * 5 = 78.57 sq.cm.

Total surface area of the metal sheet =  1174.8 + 78.57 = 1253.37 sq.cm.

Cost of 100 cm² of aluminium sheet = Rs. 70

Cost of one cm² of sheet = Rs. 0.70

Therefore cost of the bucket = 0.70 * 1253.37 = Rs. 877.36