Question

Plss solve Q 18 I am sure I will mark you brainliest

Answer 1

Internal diameter of spherical vessel = 20 cm

External diameter of hemispherical vessel = 28 cm

Internal radius = r = 10 cm and External radius = R = 14 cm

Total surface area to be painted

= External curved surface + Internal curved surface + Area of ring

= 2* pi*R^2 + 2*pi*r^2 + pi(R^2 - r^2)

= pi*(2R^2 + 2r^2 + R^2 - r^2)

= pi(3R^2 + r^2)

= 22/ 7(3 x14 x14 + 10 x 10)

=22/7 (588+100)

= 22/ 7*688

= 2162.29 cm^2

Rate of painting = 15 paise/cm2

Thus, Cost of painting = Area x Rate

= 2162*(15/100) = Rs 324.34