A man donates 10 aluminum buckets to an orphanage. A bucket made of aluminum is of height 20 cm and has its upper and lowest ends of radius 36 cm and 21 cm respectively. Find the cost of preparing 10 buckets if the cost of aluminum sheet is Rs. 42 per 100 cm^{2}.

### Answer

Surface area of bucket = π(r_{1} + r_{2})l + πr_{1}^{2}

l = √[h^{2} + (r_{2} - r_{1})^{2}]

= √625 = 25 cm

∴ Surface area of 1 bucket = 22/7 × 1866 cm^{2}

Surface area of 10 buckets = 22/7 × 18660 cm^{2}

Cost of aluminium sheet = Rs. 24631.20