Question

a hemisphercal bowl made of brass has inner diameter 10.5cm find the cost of tin plating it on the inside at the rate of Rs 16 per 100cm ​

Answer 1

Here,

We will tin-plate the inside of the hemisphere So, We need to find the curved surface area of hemisphere.

 Radius of hemisphere = r = /2 = (10.5/2) cm = 5.25 cm

 Curved surface area of the hemisphere = 22 = (2×22/7×5.25×5.25) cm2 = 173.25 cm2

Cost of tin-plating 100 cm2 = Rs 16

 

Cost of tin-plating 1 cm2 = Rs 1/100 × 16

 

Cost of tin-plating 173.25 cm2 = Rs 1/100 × 16 × 173.25 = Rs 27.72

 

∴ Cost of tin-plating the hemisphere is Rs 27.72