A hemispherical bowl has 7 cm radius. It is to be painted inside as well as outside. The cost (in ₹) of painting it at the rate of ₹6 per 4$$cm^{2}$$ is: (Use $$\pi= \frac{22}{7}$$​)

Correct option is D

Given:

Radius of hemispherical bowl  = 7cm

Cost of painting per 4$$cm^{2}$$= ₹6

Formula Used:

Curved surface area of hemisphere = $$2 \pi r^{2}$$ 

where r = radius.

Solution:

Radius of hemisphere = 7cm

Curved surface area of hemisphere = $$2 \pi (7)^{2}$$​​

​$$= 2\times \frac{22}{7}\times 49$$​​

​$$=308 \ cm^{2}$$​​

Total surface rea inside and outside is = $$2 \times 308 = 616cm^{2}$$​​

Cost of painting = $$\frac{616}{4}\times6 = ₹924$$​​