Give me the best and simple way for solving the question of class 9^{th} of Surface areas and Volumes chapter of math of question no.5 how i solve this question in easy and simple way because it is very important type of question of exercise 13.6 It costs Rs 2200 to paint the inner curved surface of a cylindrical vessel 10m deep. If the cost of painting is at the rate of Rs 20 per m2, find (i) inner curved surface area of the vessel (ii) radius of the base (iii) capacity of the vessel (Assume π = 22/7)

bhagwansinghGuru

# It costs Rs 2200 to paint the inner curved surface of a cylindrical vessel 10m deep. If the cost of painting is at the rate of Rs 20 per m2, find (i) inner curved surface area of the vessel (ii) radius of the base (iii) capacity of the vessel (Assume π = 22/7) Q.5

Share

(i) Rs 20 is the cost of painting 1 m

^{2 }area.Rs 1 is the cost to paint 1/20 m

^{2 }areaSo, Rs 2200 is the cost of painting = (1/20×2200) m

^{2 }= 110 m

^{2}areaThe inner surface area of the vessel is 110m

^{2}.(ii) Radius of the base of the vessel, let us say r.

Height (h) = 10 m and

Surface area formula = 2πrh

Using result of (i)

2πrh = 110 m

^{2}2×22/7×r×10 = 110

r = 1.75

Radius is 1.75 m.

(iii) Volume of vessel formula = πr

^{2}hHere r = 1.75 and h = 10

Volume = (22/7)×(1.75)

^{2}× 10 = 96.25Volume of vessel is 96.25 m

^{3}Therefore, the capacity of the vessel is 96.25 m

^{3}or 96250 litres.