Question

cubold. 2. Twenty cylindrical pillars of a building are to be cleaned. If the diameter of the pillar is 0.5m and height 4m, what will be cost of cleaning them at the rate of Rs.3 per m2​

Answer 1

The diameter of cylinder = 0.50 m (Given)

Therefore, radius =0.502m (As radius=Diameter2).

Radius(r) = 0.25 m

Height = 4 m (Given)

We know,

CSA of cylinder =2πrh

Substituting the values, we get:

2πrh=2×227×0.25×4

As; π=227r=0.25h=4

=2×227×25100×4

(To remove decimal)

=2×227

=447m2

CSA of 20 pillars =20×447m2

Calculating cost of cleaning:

It is given that cost of cleaning per m2 is Rs. 2.50, therefore cost of cleaning 20 pillars is given by:

CSA of 20 pillars x cost of cleaning per m2 =20×447×2.5 Rs.

= Rs. 314.28