A hemispherical bowl is made of steel, $0.25 \mathrm{cm}$ thick. The inner radius of the bowl is $5 \mathrm{cm}$. Find the outer curved surface area of the bowl. [Take $\mathrm{\pi }=\frac{22}{7}$]

The internal and external diameters of a hollow hemispherical vessel are $14 \mathrm{cm} \& 21 \mathrm{cm}$, respectively. The cost of silver plating of $1 {\mathrm{cm}}^2$ of the surface is$₹ 0.40$. Find the total cost of silver plating the vessel all over. [Take $\mathrm{\pi }=3.14$]