Ex 13.6, 5
It costs Rs 2200 to paint the inner curved surface of a cylindrical vessel 10 m deep. If the cost of painting is at the rate of Rs 20 per m2, find
(i) inner curved surface area of the vessel,
Cost of painting = Inner curved surface area Rate of painting
Rs 2200 = Inner curved surface area 20
2200/20 = Inner curved surface area
Inner curved surface area = 2200/20
Inner curved surface area = 110
Therefore, inner curved surface area of vessel = 110 m2
Ex 13.6, 5
(ii) radius of the base,
Let radius of cylinder be r
Height = h = 10 m
We know that
Curved surface area of cylinder = 110 m2
2 = 110
2 22/7 r 10 = 110
r = (110 7)/(2 22 10)
r = 7/4
r = 1.75 m
Ex 13.6, 5
(iii) capacity of the vessel.
We know that
Height = h = 10 m
Radius = r = 1.75 m = 7/4 m
Capacity of the vessel = volume = r2h
= (22/7 7/4 7/4 10) m3
= (22 1/4 7/4 10) m3
= 96.25 m3

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.