Question

5. The cost of painting the total outside surface of a closed cylinder at 3Rs per cm sq is 2744 Rs
If the height of the cylinder is 2 times the radius, then its volume is​

Answer 1

let the radius = r

then the height = 6r

cost of painting= Rs 237.60

rate of painting = Rs0.60/cm²

outer surface area of cylinder = cost of painting/rate of painting

= 237.60/0.60

=396 cm²

2πrh = 396

2 x π x r x 6r = 396

12 x 22/7 x r² = 396

396 x 7

r² = ------------

12 x 22

r² = 9

r = 3

radius = r = 3

height = 6r = 6 x 3 = 18