Question

A hollow cylindrical pipe has inner circumference 44dm and outer 45 dm. Find the cost of painting it from both sides at  Rs2 per m², if its length is 3.5m. 

Answer 1

inner circumference = 44dm = 4.4m
outer circumference = 45dm = 4.5 m
length = 3.5m
inner CSA = 4.4×3.5 = 15.4 m²
outer CSA = 4.5×3.5 = 15.75 m²
total = 15.4 + 15.75 = 31.15 m²
cost = Rs. 2 per m²
total cost = 31.15×2 = Rs. 62.30

Answer 2

✍✍HERE IS YOUR ANSWER...⬇⬇
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$\underline{SOLUTION}$ ➡



Given,

For the hollow cylindrical pipe ,

Inner circumference = 44 dm = 4.4 m

Outer circumference = 45 dm = 4.5 m

Height of the cylindrical pipe = 3.5 m

•°• Inner curved surface area = Inner circumference × Height

= 4.5 m × 3.5 m

= 15.4 sq.m


And,

Outer curved surface area = Outer circumference × Height

= 4.5 m × 3.5 m

= 15.75 sq.m


•°• Total surface area of the pipe that is to be painted = Inner curved surface area + Outer curved surface area

= ( 15.4 + 15.75 ) sq.m

= 31.15 sq.m


Now,

Cost of painting per sq.m = Rs. 2

•°• Cost of painting 31.15 sq.m = Rs. ( 2 × 31.15 )

= Rs. 62.30



$\underline{ANSWER}$ ➡ $\boxed{Rs. \: 62.30}$

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