The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white washing its curved surface area at the rate of ₹210 per 100 m².

Cost = ₹ 210 / 100 m² = ₹ 2.1 / m².

Given, l = 25 m and diameter = 14 m.

Radius = $\dfrac{\text{Diameter}}{2}$ = $\dfrac{14}{2}$ = 7m.

Curved surface area of cone = πrl.

Putting values in equation,

Curved surface area = $\dfrac{22}{7} \times 7 \times 25$ = 22 × 25 = 550 m².

Cost of white washing 1 m² = ₹ 2.1

∴ Cost of white washing 550 m² = ₹ 2.1 × 550 = ₹ 1155.

Hence, the cost of white washing 550 m² = ₹ 1155.